RGC Resources (RGCO) 10-K 8 Dec 17 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2017	Nov. 30, 2017	Mar. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Registrant Name	RGC RESOURCES INC
Entity Central Index Key	1,069,533
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		7,250,093
Entity Public Float			$ 147,136,528

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Sep. 30, 2017	Sep. 30, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 69,640	$ 643,252
Accounts receivable, net	3,492,703	3,478,983
Materials and supplies	1,021,191	824,139
Gas in storage	7,701,894	7,436,785
Prepaid income taxes	1,796,825	1,550,836
Interest rate swap	26,777	0
Other	1,576,574	1,548,329
Total current assets	15,685,604	15,482,324
UTILITY PROPERTY:
In service	204,223,714	185,577,286
Accumulated depreciation and amortization	(59,765,987)	(56,156,287)
In service, net	144,457,727	129,420,999
Construction work in progress	3,470,244	2,707,139
Utility plant, net	147,927,971	132,128,138
OTHER ASSETS:
Regulatory assets	11,796,260	14,332,451
Investment in unconsolidated affiliate	7,445,106	3,496,404
Interest rate swap	90,066	0
Other	190,064	113,532
Total other assets	19,521,496	17,942,387
TOTAL ASSETS	183,135,071	165,552,849
CURRENT LIABILITIES:
Line-of-credit	0	14,556,785
Dividends payable	1,050,281	970,244
Accounts payable	5,122,899	5,345,575
Capital contributions payable	1,055,504	287,794
Customer credit balances	1,220,578	1,605,608
Customer deposits	1,471,960	1,627,105
Accrued expenses	3,006,936	3,194,255
Over-recovery of gas costs	1,438,074	909,687
Total current liabilities	14,366,232	28,497,053
LONG-TERM DEBT:
Notes payable	43,812,200	33,896,200
Line-of-credit	17,791,760	0
Less unamortized debt issuance costs	(291,949)	(260,149)
Long-term debt net of unamortized debt issuance costs	61,312,011	33,636,051
DEFERRED CREDITS AND OTHER LIABILITIES:
Asset retirement obligations	6,069,993	5,682,556
Regulatory cost of retirement obligations	10,055,189	9,348,443
Benefit plan liabilities	8,214,326	13,763,820
Deferred income taxes	23,076,848	18,957,854
Total deferred credits and other liabilities	47,416,356	47,752,673
COMMITMENTS AND CONTINGENCIES (Note 11)
Stockholders’ Equity:
Common Stock, $5 par value; authorized 10,000,000 shares; issued and outstanding 7,240,846 and 7,182,434 shares in 2017 and 2016, respectively	36,204,230	23,941,445
Preferred stock, no par; authorized 5,000,000 shares; no shares issued and outstanding in 2017 and 2016	0	0
Capital in excess of par value	292,485	9,509,548
Retained earnings	24,746,021	24,713,310
Accumulated other comprehensive loss	(1,202,264)	(2,497,231)
Total stockholders’ equity	60,040,472	55,667,072
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 183,135,071	$ 165,552,849

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Sep. 30, 2016
Statement of Financial Position [Abstract]
Common stock, par value (in usd per share)	$ 5	$ 5
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	7,240,846	7,182,434
Common stock, share outstanding	7,240,846	7,182,434
Preferred stock, no par value (in usd per share)	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, share outstanding	0	0

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
OPERATING REVENUES:
Gas utilities	$ 61,252,015	$ 58,079,990	$ 67,094,290
Other	1,044,855	983,301	1,095,317
Total operating revenues	62,296,870	59,063,291	68,189,607
COST OF SALES:
Gas utilities	28,919,625	27,009,330	37,437,315
Other	568,088	489,047	545,859
Total cost of sales	29,487,713	27,498,377	37,983,174
GROSS MARGIN	32,809,157	31,564,914	30,206,433
OTHER OPERATING EXPENSES:
Operations and maintenance	13,100,041	13,098,086	13,486,885
General taxes	1,786,070	1,663,126	1,606,421
Depreciation and amortization	6,256,737	5,591,610	5,106,935
Total other operating expenses	21,142,848	20,352,822	20,200,241
OPERATING INCOME	11,666,309	11,212,092	10,006,192
Equity in earnings of unconsolidated affiliate	421,646	152,864	0
Other expense, net	132,446	255,585	228,796
Interest expense	1,917,254	1,636,321	1,512,419
INCOME BEFORE INCOME TAXES	10,038,255	9,473,050	8,264,977
INCOME TAX EXPENSE	3,805,390	3,666,184	3,170,562
NET INCOME	$ 6,232,865	$ 5,806,866	$ 5,094,415
EARNINGS PER COMMON SHARE:
Basic (in usd per share)	$ 0.86	$ 0.81	$ 0.72
Diluted (in usd per share)	$ 0.86	$ 0.81	$ 0.72
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)	7,218,686	7,149,906	7,092,315
Diluted (in shares)	7,256,046	7,159,763	7,097,514

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 6,232,865	$ 5,806,866	$ 5,094,415
Other comprehensive income, net of tax:
Interest rate swaps	72,489	0	0
Defined benefit plans	1,222,478	(210,686)	(1,147,219)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	1,294,967	(210,686)	(1,147,219)
COMPREHENSIVE INCOME	$ 7,527,832	$ 5,596,180	$ 3,947,196

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Sep. 30, 2014	$ 52,020,847	$ 23,601,890	$ 8,237,228	$ 21,321,055	$ (1,139,326)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,094,415			5,094,415
Other comprehensive income (loss)	(1,147,219)				(1,147,219)
Exercise of stock options	49,366	13,000	36,366
Stock option grants	83,640		83,640
Cash dividends declared	(3,643,093)			(3,643,093)
Issuance of common stock	383,035	92,600	290,435
Ending balance at Sep. 30, 2015	52,840,991	23,707,490	8,647,669	22,772,377	(2,286,545)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,806,866			5,806,866
Other comprehensive income (loss)	(210,686)				(210,686)
Exercise of stock options	41,762	11,000	30,762
Stock option grants	64,640		64,640
Cash dividends declared	(3,865,933)			(3,865,933)
Issuance of common stock	989,432	222,955	766,477
Ending balance at Sep. 30, 2016	55,667,072	23,941,445	9,509,548	24,713,310	(2,497,231)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,232,865			6,232,865
Other comprehensive income (loss)	1,294,967				1,294,967
Exercise of stock options	142,241	50,250	91,991
Stock option grants	73,780		73,780
Cash dividends declared	(4,195,910)			(4,195,910)
Stock split	0	12,029,790	(10,025,546)	(2,004,244)
Issuance costs	(96,508)		(96,508)
Issuance of common stock	921,965	182,745	739,220
Ending balance at Sep. 30, 2017	$ 60,040,472	$ 36,204,230	$ 292,485	$ 24,746,021	$ (1,202,264)

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Statement of Stockholders' Equity [Abstract]
Dividends declared (in usd per share)	$ 0.58	$ 0.54	$ 0.51
Issuance of stock (in shares)	47,187	66,887	27,780
Options exercised (in shares)	11,225	3,300	3,900

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 6,232,865	$ 5,806,866	$ 5,094,415
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and amortization	6,378,368	5,709,525	5,219,893
Cost of retirement of utility plant, net	(354,744)	(449,201)	(406,731)
Stock option grants	73,780	64,640	83,640
Equity in earnings of unconsolidated affiliate	(421,646)	(152,864)	0
Deferred income taxes	3,325,379	4,466,954	2,416,841
Other noncash items, net	203,743	197,298	105,815
Changes in assets and liabilities which provided (used) cash:
Accounts receivable and customer deposits, net	(191,386)	(258,960)	638,917
Inventories and gas in storage	(462,161)	867,682	3,168,056
Over/under recovery of gas costs	528,387	(991,739)	2,082,257
Other assets	(956,894)	(398,864)	(768,922)
Accounts payable, customer credit balances and accrued expenses, net	(1,374,713)	60,303	(873,354)
Total adjustments	6,748,113	9,114,774	11,666,412
Net cash provided by operating activities	12,980,978	14,921,640	16,760,827
CASH FLOWS FROM INVESTING ACTIVITIES:
Expenditures for utility property	(20,750,181)	(17,945,719)	(13,780,356)
Investment in unconsolidated affiliate	(2,759,346)	(3,055,746)	0
Proceeds from disposal of utility property	16,972	4,964	30,082
Net cash used in investing activities	(23,492,555)	(20,996,501)	(13,750,274)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under line-of-credit	42,569,303	38,310,326	34,698,924
Repayments under line-of-credit	(39,334,328)	(33,094,539)	(34,402,977)
Proceeds from issuance of unsecured notes	9,916,000	3,396,200	0
Debt issuance expenses	(64,835)	(101,619)	0
Proceeds from issuance of stock	967,698	1,031,194	432,401
Cash dividends paid	(4,115,873)	(3,808,683)	(3,603,424)
Net cash provided by (used in) financing activities	9,937,965	5,732,879	(2,875,076)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(573,612)	(341,982)	135,477
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	643,252	985,234	849,757
CASH AND CASH EQUIVALENTS AT END OF YEAR	69,640	643,252	985,234
Cash paid (refunded) during the year for:
Interest	1,734,178	1,480,665	1,002,462
Income taxes	$ 726,000	$ (907,000)	$ 1,266,573

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation —RGC Resources, Inc. is an energy services company primarily engaged in the sale and distribution of natural gas. The consolidated financial statements include the accounts of RGC Resources, Inc. and its wholly owned subsidiaries (“Resources” or the “Company”): Roanoke Gas Company (“Roanoke Gas”); Diversified Energy Company; RGC Ventures of Virginia, Inc., operating as Application Resources and The Utility Consultants; and RGC Midstream, LLC. Roanoke Gas is a natural gas utility, which distributes and sells natural gas to approximately 59,800 residential, commercial and industrial customers within its service areas in Roanoke, Virginia and the surrounding localities. The Company’s business is seasonal in nature as a majority of natural gas sales are for space heating during the winter season. Roanoke Gas is regulated by the Virginia State Corporation Commission (“SCC” or “Virginia Commission”). RGC Ventures of Virginia, Inc. was dissolved in 2016 after Application Resources, which provided information system services to software providers in the utility industry, ceased operations in 2016, and The Utility Consultants, which provided regulatory consulting services to other utilities, ceased operations in 2015. RGC Midstream, LLC is a wholly-owned subsidiary created in 2015 to invest in the Mountain Valley pipeline project. Diversified Energy Company is currently inactive. The Company follows accounting and reporting standards established by the Financial Accounting Standards Board (“FASB”) and the Securities and Exchange Commission (“SEC”). Resources has only one reportable segment as defined under FASB ASC No. 280 – Segment Reporting . All intercompany transactions have been eliminated in consolidation. Rate Regulated Basis of Accounting —The Company’s regulated operations follow the accounting and reporting requirements of FASB ASC No. 980, Regulated Operations . The economic effects of regulation can result in a regulated company deferring costs that have been or are expected to be recovered from customers in a period different from the period in which the costs would be charged to expense by an unregulated enterprise. When this situation occurs, costs are deferred as assets in the consolidated balance sheet (regulatory assets) and recorded as expenses when such amounts are reflected in rates. Additionally, regulators can impose liabilities upon a regulated company for amounts previously collected from customers and for current collection in rates of costs that are expected to be incurred in the future (regulatory liabilities). In the event the provisions of FASB ASC No. 980 no longer apply to any or all regulatory assets or liabilities, the Company would write off such amounts and include them in the consolidated statements of income and comprehensive income in the period for which FASB ASC No. 980 no longer applied. Regulatory assets and liabilities included in the Company’s consolidated balance sheets as of September 30, 2017 and 2016 are as follows: September 30 2017 2016 Regulatory Assets: Current Assets: Accounts receivable: Accrued WNA revenues $ 248,840 $ 148,663 Other: Accrued pension and postretirement medical 658,786 835,704 Utility Property: In service: Other 11,945 11,945 Other Assets: Regulatory assets: Premium on early retirement of debt 1,941,182 2,055,369 Accrued pension and postretirement medical 8,643,524 11,460,738 Other 1,211,554 816,344 Total regulatory assets $ 12,715,831 $ 15,328,763 Regulatory Liabilities: Current Liabilities: Over-recovery of gas costs $ 1,438,074 $ 909,687 Accrued expenses: Over-recovery of SAVE Plan revenues 215,514 238,694 Deferred Credits and Other Liabilities: Asset retirement obligations 6,069,993 5,682,556 Regulatory cost of retirement obligations 10,055,189 9,348,443 Total regulatory liabilities $ 17,778,770 $ 16,179,380 As of September 30, 2017 , the Company had regulatory assets in the amount of $12,703,886 on which the Company did not earn a return during the recovery period. These assets primarily pertain to the net funded position of the Company’s benefit plans related to its regulated operations. As such, the amortization period is not specifically defined. Utility Plant and Depreciation —Utility plant is stated at original cost and includes direct labor and materials, contractor costs, and all allocable overhead charges. The Company applies the group method of accounting, where the costs of like assets are aggregated and depreciated by applying a rate based on the average expected useful life of the assets. In accordance with Company policy, expenditures for depreciable assets with a life greater than one year are capitalized, along with any upgrades or improvements to existing assets, when they significantly improve or extend the original expected useful life of an asset. Expenditures for maintenance, repairs, and minor renewals and betterments are expensed as incurred. The original cost of depreciable property retired is removed from utility plant and charged to accumulated depreciation. The cost of asset removals, less salvage, is charged to “regulatory cost of retirement obligations” or “asset retirement obligations” as explained under Asset Retirement Obligations below. Utility plant is composed of the following major classes of assets: Years Ended September 30 2017 2016 Distribution and transmission $ 177,845,619 $ 160,354,300 LNG storage 13,299,288 12,594,294 General and miscellaneous 13,078,807 12,628,692 Total utility plant in service $ 204,223,714 $ 185,577,286 Provisions for depreciation are computed principally at composite straight-line rates over periods ranging from 5 to 76 years . Rates are determined by depreciation studies which are required to be performed at least every 5 years on the regulated utility assets of Roanoke Gas. The Company completed its last depreciation study in June 2014. The composite weighted-average depreciation rate realized using the most recently completed depreciation study was 3.29% for the fiscal year ended September 30, 2017 and 3.25% for the fiscal years ended September 30, 2016 and 2015. The composite rates are composed of two components, one based on average service life and one based on cost of retirement. As a result, the Company accrues the estimated cost of retirement of long-lived assets through depreciation expense. Retirement costs are not a legal obligation but rather the result of cost-based regulation and are accounted for under the provisions of FASB ASC No. 980. Such amounts are classified as a regulatory liability. The Company reviews long-lived assets and certain identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. These reviews have not identified any impairments which would have a material effect on the results of operations or financial condition. Asset Retirement Obligations —FASB ASC No. 410, Asset Retirement and Environmental Obligations , requires entities to record the fair value of a liability for an asset retirement obligation when there exists a legal obligation for the retirement of the asset. When the liability is initially recorded, the entity capitalizes the cost, thereby increasing the carrying amount of the underlying asset. In subsequent periods, the liability is accreted, and the capitalized cost is depreciated over the useful life of the underlying asset. The Company has recorded asset retirement obligations for its future legal obligations related to purging and capping its distribution mains and services upon retirement, although the timing of such retirements is uncertain. The Company’s composite depreciation rates include a component to provide for the cost of retirement of assets. As a result, the Company accrues the estimated cost of retirement of its utility plant through depreciation expense and creates a corresponding regulatory liability. The costs of retirement considered in the development of the depreciation component include those costs associated with the legal liability. Therefore, the asset retirement obligation is reclassified from the regulatory cost of retirement obligation. If the legal obligations were to exceed the regulatory liability provided for in the depreciation rates, the Company would establish a regulatory asset for such difference with the anticipation of future recovery through rates charged to customers. In 2017, the Company increased its asset retirement obligation to reflect revisions to the estimated cash flows for asset retirements. The following is a summary of the asset retirement obligation: Years Ended September 30 2017 2016 Beginning balance $ 5,682,556 $ 5,295,868 Liabilities incurred 65,556 85,263 Liabilities settled (137,304 ) (176,090 ) Accretion 312,503 310,568 Revisions to estimated cash flows 146,682 166,947 Ending balance $ 6,069,993 $ 5,682,556 Cash, Cash Equivalents and Short-Term Investments —From time to time, the Company will have balances on deposit at banks in excess of the amount insured by the Federal Deposit Insurance Corporation (“FDIC”). The Company has not experienced any losses on these accounts and does not consider these amounts to be at credit risk. As of September 30, 2017 , the Company did not have any bank deposits in excess of the FDIC insurance limits. For purposes of the consolidated statements of cash flows, the Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents. Customer Receivables and Allowance for Doubtful Accounts —Accounts receivable include amounts billed to customers for natural gas sales and related services and gas sales occurring subsequent to normal billing cycles but before the end of the period. The Company provides an estimate for losses on these receivables by utilizing historical information, current account balances, account aging and current economic conditions. Customer accounts are charged off annually when deemed uncollectible or when turned over to a collection agency for action. A reconciliation of changes in the allowance for doubtful accounts is as follows: Years Ended September 30 2017 2016 2015 Beginning balance $ 76,934 $ 52,721 $ 70,747 Provision for doubtful accounts 84,587 14,074 87,908 Recoveries of accounts written off 110,725 137,055 139,282 Accounts written off (172,790 ) (126,916 ) (245,216 ) Ending balance $ 99,456 $ 76,934 $ 52,721 Financing Receivables —Financing receivables represent a contractual right to receive money either on demand or on fixed or determinable dates and are recognized as assets on the entity’s balance sheet. Trade receivables are the Company's one primary type of financing receivables, resulting from the sale of natural gas and other services to its customers. These receivables are short-term in nature with a provision for uncollectible balances included in the financial statements. Inventories —Inventories, consisting of natural gas in storage and materials and supplies, are recorded at average cost. Injections into storage are priced at the purchase cost at the time of injection and withdrawals from storage are priced at the weighted average price in storage. Materials and supplies are removed from inventory at average cost. Unbilled Revenues —The Company bills its natural gas customers on a monthly cycle; however, the billing cycle period for most customers does not coincide with the accounting periods used for financial reporting. As the Company recognizes revenue when gas is delivered, an accrual is made to estimate revenues for natural gas delivered to customers but not billed during the accounting period. The amounts of unbilled revenue receivable included in accounts receivable on the consolidated balance sheets at September 30, 2017 and 2016 were $965,683 and $1,004,061 , respectively. Income Taxes —Income taxes are accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the years in which those temporary differences are expected to be recovered or settled. A valuation allowance against deferred tax assets is provided if it is more likely than not the deferred tax asset will not be realized. The Company and its subsidiaries file state and federal consolidated income tax returns. Debt Expenses —Debt issuance expenses are deferred and amortized over the lives of the debt instruments. The unamortized balances are offset against the carrying value of long-term debt. Over/Under-Recovery of Natural Gas Costs —Pursuant to the provisions of the Company’s Purchased Gas Adjustment (“PGA”) clause, the SCC provides the Company with a method of passing along to its customers increases or decreases in natural gas costs incurred by its regulated operations, including gains and losses on natural gas derivative hedging instruments. On a quarterly basis, the Company files a PGA rate adjustment request with the SCC to adjust the gas cost component of its rates up or down depending on projected price and activity. Once administrative approval is received, the Company adjusts the gas cost component of its rates to reflect the approved amount. As actual costs will differ from the projections used in establishing the PGA rate, the Company may either over-recover or under-recover its actual gas costs during the period. Any difference between actual costs incurred and costs recovered through the application of the PGA is recorded as a regulatory asset or liability. At the end of the deferral period, the balance of the net deferred charge or credit is amortized over an ensuing 12 -month period as amounts are reflected in customer billings. Fair Value —Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company determines fair value based on the following fair value hierarchy which prioritizes each input to the valuation methods into one of the following three broad levels: • Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2 – Inputs other than quoted prices in Level 1 that are either for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3 – Unobservable inputs for the asset or liability where there is little, if any, market activity which require the Company to develop its own assumptions. The fair value hierarchy gives the highest priority to unadjusted quoted prices in active markets (Level 1) and the lowest priority to unobservable inputs (Level 3). All fair value disclosures are categorized within one of the three categories in the hierarchy. See fair value disclosures below and in Notes 8 and 12. Use of Estimates —The preparation of financial statements in conformity with Generally Accepted Accounting Principles in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Excise and Sales Taxes —Certain excise and sales taxes imposed by the state and local governments in the Company’s service territory are collected by the Company from its customers. These taxes are accounted for on a net basis and therefore are not included as revenues in the Company’s Consolidated Statements of Income. Earnings Per Share —Basic earnings per share and diluted earnings per share are calculated by dividing net income by the weighted-average common shares outstanding during the period and the weighted-average common shares outstanding during the period plus dilutive potential common shares, respectively. Dilutive potential common shares are calculated in accordance with the treasury stock method, which assumes that proceeds from the exercise of all options are used to repurchase common stock at market value. The amount of shares remaining after the proceeds are exhausted represents the potentially dilutive effect of the securities. A reconciliation of basic and diluted earnings per share is presented below: Years Ended September 30 2017 2016 2015 Net Income $ 6,232,865 $ 5,806,866 $ 5,094,415 Weighted-average common shares 7,218,686 7,149,906 7,092,315 Effect of dilutive securities: Options to purchase common stock 37,360 9,857 5,199 Diluted average common shares 7,256,046 7,159,763 7,097,514 Earnings Per Share of Common Stock: Basic $ 0.86 $ 0.81 $ 0.72 Diluted $ 0.86 $ 0.81 $ 0.72 Business and Credit Concentrations — The primary business of the Company is the distribution of natural gas to residential, commercial and industrial customers in its service territories. No sales to individual customers accounted for more than 5% of total revenue in any period or amounted to more than 5% of total accounts receivable. Roanoke Gas currently holds the only franchises and certificates of public convenience and necessity to distribute natural gas in its service area. These franchises are effective through January 1, 2036 . The Company's current certificates of public convenience and necessity in Virginia are exclusive and are intended for perpetual duration. Roanoke Gas is served directly by two primary pipelines that provide all of the natural gas supplied to the Company’s customers. Depending upon weather conditions and the level of customer demand, failure of one or both of these transmission pipelines could have a major adverse impact on the Company. Derivative and Hedging Activities —FASB ASC No. 815, Derivatives and Hedging , requires the recognition of all derivative instruments as assets or liabilities in the Company’s balance sheet and measurement of those instruments at fair value. The Company’s hedging and derivatives policy allows management to enter into derivatives for the purpose of managing the commodity and financial market risks of its business operations. The Company’s hedging and derivatives policy specifically prohibits the use of derivatives for speculative purposes. The key market risks that RGC Resources, Inc. hedges against include the price of natural gas and the cost of borrowed funds. The Company historically has entered into collars, swaps and caps for the purpose of hedging the price of natural gas in order to provide price stability during the winter months. The fair value of these instruments is recorded in the balance sheet with the offsetting entry to either under-recovery of gas costs or over-recovery of gas costs. Net income and other comprehensive income are not affected by the change in market value as any cost incurred or benefit received from these instruments is recoverable or refunded through the PGA as the SCC allows for full recovery of prudent costs associated with natural gas purchases. At September 30, 2017 and 2016 , the Company had no outstanding derivative instruments for the purchase of natural gas. The Company had one interest rate swap associated with its $7,000,000 term note with Branch Banking & Trust as discussed in Note 6. Effective November 1, 2017, the swap agreement converts the floating rate note based on LIBOR into a fixed rate debt with a 2.30% effective interest rate. The swap qualifies as a cash flow hedge with changes in fair value reported in other comprehensive income. No portion of the swap was deemed ineffective during the period. The table below reflects the fair value of the derivative instrument and its corresponding classification in the consolidated balance sheets. September 30 2017 2016 Derivatives designated as hedging instruments: Current assets: Interest rate swap $ 26,777 $ — Other assets: Interest rate swap $ 90,066 $ — Total derivatives designated as hedging instruments $ 116,843 $ — The fair value of the interest rate swap is determined by using the counter party's proprietary models and certain assumptions regarding past, present and future market conditions. See Note 12 for additional information on fair value. Non-Cash Activity — A non-cash increase in investment in unconsolidated affiliate and corresponding increase in capital contributions payable of $767,710 and $287,794 occurred for the fiscal years ended September 30, 2017 and 2016, respectively. Other Comprehensive Income (Loss) — A summary of other comprehensive income is provided below: Before Tax Amount Tax (Expense) or Benefit Net of Tax Amount Year Ended September 30, 2017: Interest rate swap: Unrealized gains $ 116,843 $ (44,354 ) $ 72,489 Net interest rate swap 116,843 (44,354 ) 72,489 Defined benefit plans: Net gain arising during period $ 1,715,505 $ (651,892 ) $ 1,063,613 Amortization of actuarial losses 256,234 (97,369 ) 158,865 Net defined benefit plans 1,971,739 (749,261 ) 1,222,478 Other comprehensive income $ 2,088,582 $ (793,615 ) $ 1,294,967 Year Ended September 30, 2016: Defined benefit plans: Net loss arising during period $ (560,887 ) $ 213,137 $ (347,750 ) Amortization of actuarial losses 221,070 (84,006 ) 137,064 Net defined benefit plans (339,817 ) 129,131 (210,686 ) Other comprehensive loss $ (339,817 ) $ 129,131 $ (210,686 ) Year Ended September 30, 2015: Defined benefit plans: Net loss arising during period (1,910,573 ) 726,017 (1,184,556 ) Amortization of actuarial losses 60,221 (22,884 ) 37,337 Net defined benefit plans (1,850,352 ) 703,133 (1,147,219 ) Other comprehensive loss $ (1,850,352 ) $ 703,133 $ (1,147,219 ) The amortization of actuarial losses is included as a component of net periodic pension and postretirement benefit costs in operations and maintenance expense. Composition of Accumulated Other Comprehensive Income (Loss): Interest Rate Swaps Defined Benefit Plans Accumulated Other Comprehensive Income (Loss) Balance September 30, 2014 $ — $ (1,139,326 ) $ (1,139,326 ) Other comprehensive income (loss) — (1,147,219 ) (1,147,219 ) Balance September 30, 2015 — (2,286,545 ) (2,286,545 ) Other comprehensive income (loss) — (210,686 ) (210,686 ) Balance September 30, 2016 — (2,497,231 ) (2,497,231 ) Other comprehensive income (loss) 72,489 1,222,478 1,294,967 Balance September 30, 2017 $ 72,489 $ (1,274,753 ) $ (1,202,264 ) Recently Adopted Accounting Standards —In November 2015, the FASB issued ASU 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes . The ASU requires that all deferred tax assets and liabilities be presented as noncurrent and eliminates prior guidance to classify and present deferred tax assets and liabilities as current and noncurrent. This ASU is effective for the Company for the annual reporting period ended September 30, 2018 and interim periods within that annual period. Early application is permitted. The Company adopted this ASU for the quarter ended December 31, 2015. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting . The guidance simplifies several aspects of the accounting for share-based payment award transactions, including income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The new guidance is effective for the Company for the annual reporting period ending September 30, 2018 and interim periods within that annual period. Early adoption is permitted. The Company adopted this ASU for the quarter ended September 30, 2016. Under the prior guidance, excess tax benefits were to be tracked in an APIC pool and not recognized in the income statement. Tax deficiencies were netted against the accumulated APIC pool and only recognized in the income statement starting at the time tax deficiencies exceeded the pool. Under ASU 2016-09, the APIC pool is eliminated with all excess tax benefits and deficiencies recognized in income tax expense on the income statement. Prior to the adoption of this ASU, stock option activity did not result in the accumulation of an APIC pool; therefore, adopting the ASU had minimal impact on the Company’s current financial position, results of operations or cash flows and no impact on prior results. In January 2017, the FASB issued ASU 2017-03, Accounting Changes and Error Corrections and Investments - Equity Method and Joint Ventures . This update adds the text of the SEC Staff Announcement, Disclosure of the Impact That Recently Issued Accounting Standards Will Have on the Financial Statements of a Registrant When Such Standards Are Adopted in a Future Period (in accordance with Staff Accounting Bulletin Topic 11.M) as paragraph 250-10-S99-6. Related specifically to ASU 2014-09, ASU 2016-02 and ASU 2016-13, an SEC registrant should evaluate ASUs that have not yet been adopted to determine and include appropriate financial disclosures and MD&A discussions, including consideration of additional qualitative disclosures, to assist financial statement readers in assessing the significance of impact on adoption. The new guidance is effective immediately. The nature of this guidance relates to the effectiveness and quality of disclosures related to ASUs not yet adopted; however, there is no effect on the Company's financial position, results of operations or cash flows. Recently Issued Accounting Standards —In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) that affects any entity that enters into contracts with customers for the transfer of goods or services or transfer of non-financial assets. This guidance supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. The core principle of the new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contract with the customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when, or as, the entity satisfies the performance obligation. In August 2015, the FASB issued ASU 2015-14 that deferred the effective date of this guidance by one year making the standard effective for the Company's annual reporting period ending September 30, 2019 and interim periods within that annual period. The FASB continues to issue subsequent guidance under ASC No. 606 to provide further clarification of the original ASU. In addition, the Company is also monitoring the activity of the Power and Utilities Task Force. The Task Force was formed by the American Institute of Certified Public Accountants ("AICPA") in an effort to provide industry-specific guidance. Implementation issues identified by the Task Force include accounting for contributions in aid of construction and assessing collectability of customer accounts when regulated mechanisms exist to allow recovery of uncollected accounts from ratepayers. As of September 30, 2017, the Company continues identifying sources of revenue and evaluating the effect that the revenue guidance will have on financial results and disclosures. Though the evaluation is ongoing, based on the review of customer contracts to date, the Company is not anticipating a material impact to its financial position, results of operations or cash flows upon adoption; however, the Company does anticipate the potential for significant new disclosures as a result of the guidance. Because of ongoing internal analysis and the continued activities of the FASB and other related implementation efforts regarding the rate-regulated natural gas industry, early adoption is not expected. The Company will consider all current and future guidance, including the conclusions of the Task Force, before determining how best to implement the new revenue recognition standard. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities . The ASU enhances the reporting model for financial instruments to provide users of the financial statements with more useful information through several provisions, including the following: (1) requires equity investments, excluding investments accounted for under the equity method, be measured at fair value with changes in fair value recognized in net income, (2) simplifies the impairment assessment of equity investments without readily determinable fair values, (3) eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet, (4) requires entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, and (5) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. The new guidance is effective for the Company for the annual reporting period ending September 30, 2019 and interim periods within that annual period. Management has not completed its evaluation of the new guidance. However, the Company does not currently expect the new guidance to have a material effect on its financial position, results of operations or cash flows. In February 2016, the FASB issued ASU 2016-02, Leases. The ASU leaves the accounting for leases mostly unchanged for lessors, with the exception of targeted improvements for consistency; however, the new guidance requires lessees to recognize assets and liabilities for leases with terms of more than 12 months. The ASU also revises the definition of a lease as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. Consistent with current GAAP, the presentation and cash flows arising from a lease by a lessee will primarily depend on its classification as a finance or operating lease. In contrast, the new ASU requires both types of leases to be recognized on the balance sheet. In addition, the new guidance includes quantitative and qualitative disclosure requirements to aid financial statement users in better understanding the amount, timing and uncertainty of cash flows arising from leases. The new guidance is effective for the Company for the annual reporting period ending September 30, 2020 and interim periods within that annual period. Early adoption is permitted. Management has not completed its evaluation of the new guidance. However, the Company has completed its inventory of leases and does not currently expect the new guidance to have a material effect on its financial position, results of operations or cash flows. In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits . The primary objective of this guidance is to improve the financial statement presentation of net periodic pension and postretirement benefit costs; however, it also changes which cost components are eligible for capitalization. The amendments in the ASU require that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and, if a subtotal for income from operations is presented, outside of income from operations. In addition, the ASU allows only the service cost component of periodic benefit cost to be eligible for capitalization when applica

Stock Split

Stock Split	12 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Stock Split	STOCK SPLIT On January 17, 2017, Resources Board of Directors approved a three-for-two stock split of the Company's issued and outstanding common stock. The stock split was effected in the form of a 50% stock dividend entitling each shareholder to receive one additional share of common stock for every two shares owned. The stock dividend was payable March 1, 2017 to shareholders of record on February 15, 2017. As the par value of the common stock remained at $5 per share, the Company reclassified $10,025,546 from "Capital in excess of par value" and $2,004,244 from "Retained earnings" to "Common stock" associated with the issuance of 2,405,958 shares. Corresponding prior year amounts of share and per share data have been restated retrospectively to reflect the 50% stock dividend.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Sep. 30, 2017
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS The SCC exercises regulatory authority over the natural gas operations of Roanoke Gas. Such regulation encompasses terms, conditions and rates to be charged to customers for natural gas service, safety standards, service extension, accounting and depreciation. On June 30, 2017, the Company filed with the SCC its most recent SAVE (Steps to Advance Virginia's Energy) Plan and Rider. The SAVE Plan provides a mechanism for the Company to recover the related depreciation and expenses and return on rate base of the additional capital investment without the filing of a formal application for an increase in non-gas base rates. Under the current application, the Company submitted its report for collecting the shortfall in SAVE revenues collected under the 2016 SAVE Plan and proposed new 2018 SAVE rates to be implemented for the ongoing investment in SAVE Plan projects. On September 28, 2017, the Company received approval of its application to implement the new 2018 SAVE rates related to proposed qualifying SAVE investments in calendar 2018. The SCC also approved the True-Up factor to provide collection on the remaining under-collected 2016 SAVE Plan for a modification to the SAVE Plan and Rider.

Other Investments

Other Investments	12 Months Ended
	Sep. 30, 2017
Other Investments [Abstract]
Other Investments	OTHER INVESTMENTS In October 2015, the Company, through its wholly-owned subsidiary, RGC Midstream, LLC ("Midstream"), acquired a 1% equity interest in the Mountain Valley Pipeline, LLC (the “LLC”). The LLC was established to construct and operate a natural gas pipeline originating in northern West Virginia and extending through south central Virginia. The proposed pipeline will have the capacity to transport approximately 2 million decatherms of natural gas per day. On October 13, 2017, the Federal Energy Regulatory Commission issued the Certificate of Public Convenience and Necessity subject to certain conditions and requirements. With FERC approval, the LLC will continue the process of obtaining the necessary approvals and permits from other federal and state government agencies. Assuming no significant delays in the permitting process, the pipeline is expected to be in service by late 2018. The total project cost is estimated to be approximately $3.5 billion. The Company's 1% equity interest in the LLC will require a total estimated cash investment of approximately $35 million, provided by periodic capital contributions throughout the design and construction phases of the project. Midstream held an approximate $7.4 million equity method investment in the LLC at September 30, 2017 . Initial funding for Midstream's investment in the LLC is provided through two unsecured Promissory Notes, each with a 5 -year term, as further described in Note 6 below. The Company will participate in the earnings generated from the transportation of natural gas through the pipeline in proportion to its level of investment. The financial statement locations of the investment in the LLC are as follows: September 30 Balance Sheet Location of Other Investments: 2017 2016 Other Assets: Investment in unconsolidated affiliate $ 7,445,106 $ 3,496,404 Current Liabilities: Capital contributions payable $ 1,055,504 $ 287,794 For the Years ended September 30 Income Statement Location of Other Investments: 2017 2016 2015 Equity in earnings of unconsolidated affiliate $ 421,646 $ 152,864 $ —

Line-of-Credit

Line-of-Credit	12 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Line-of-Credit	LINE-OF-CREDIT On March 27, 2017, Roanoke Gas entered into a new unsecured line-of-credit agreement. This line-of-credit agreement replaced the agreement which expired on March 31, 2017. The expired agreement was for a term of one year and all amounts drawn against that agreement were considered to be current liabilities. The new line-of-credit agreement is for a two -year term expiring March 31, 2019. Amounts drawn against the new agreement are considered to be non-current as the balance under the line-of-credit is not subject to repayment within the next 12-month period. Except for the two -year term, the new agreement maintains the same variable interest rate based on 30-day LIBOR plus 100 basis points and availability fee of 15 basis points as the expired agreement. The new agreement also maintains the multi-tiered borrowing limits to accommodate seasonal borrowing demands and minimize borrowing costs. Available limits under this agreement for the remaining term are as follows: As of Available Line-of-Credit September 30, 2017 $ 21,000,000 March 1, 2018 17,000,000 July 22, 2018 22,000,000 September 22, 2018 30,000,000 A summary of the line-of-credit follows: September 30 2017 2016 2015 Line-of-credit at year-end $ 21,000,000 $ 24,000,000 $ 24,000,000 Outstanding balance at year-end 17,791,760 14,556,785 9,340,997 Highest month-end balance outstanding 17,791,760 15,246,089 17,366,052 Average daily balance 10,936,114 9,620,914 6,377,040 Average rate of interest during year on outstanding balances 1.92 % 1.40 % 1.17 % Interest rate at year-end 2.23 % 1.53 % 1.20 % Interest rate on unused line-of-credit 0.15 % 0.15 % 0.15 % Associated with the line-of-credit is a credit agreement that contains various representations, warranties and covenants including a requirement that the Company maintain an interest coverage ratio of not less than 1.5 to 1 and a long-term debt to long-term capitalization ratio of less than 65% .

Long-Term Debt

Long-Term Debt	12 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT On November 1, 2016, Roanoke Gas entered into a 5 -year unsecured note with Branch Banking & Trust in the principal amount of $7,000,000 . The note is variable rate with interest based on 30-day LIBOR plus 90 basis points. In addition, Roanoke Gas also entered into a swap agreement with Branch Banking & Trust to convert the variable rate debt into a fixed-rate instrument with an annual interest rate of 2.30% . The swap agreement is not effective until November 1, 2017, with the monthly interest rate on the note floating until the swap period begins. The proceeds from the note were used to convert a portion of the Company's line-of-credit balance into longer-term financing. Midstream has two unsecured Promissory Notes ("Notes") which provide up to a total of $25 million in borrowing limits over a period of 5 years , with an interest rate of 30-day LIBOR plus 160 basis points. Midstream issued the Notes in December 2015 to provide financing for capital investment in respect of its 1% interest in the LLC. In accordance with the terms of the debt, at such point in time as Midstream has borrowed $17.5 million under the Notes, Midstream is required to provide the next $5 million towards its capital contributions to the LLC. Once Midstream has completed its $5 million in contributions, it may resume borrowing under the Notes up to the $25 million limit. Long-term debt consists of the following: September 30 2017 2016 Principal Unamortized Debt Issuance Costs Principal Unamortized Debt Issuance Costs Roanoke Gas Company: Unsecured senior notes payable, at 4.26%, due on September 18, 2034 $ 30,500,000 $ 164,119 $ 30,500,000 $ 173,773 Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 7,000,000 13,618 — — Pending unsecured note — 48,160 — — RGC Midstream, LLC: Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020 $ 6,312,200 $ 66,052 $ 3,396,200 $ 86,376 Total notes payable $ 43,812,200 $ 291,949 $ 33,896,200 $ 260,149 Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019 17,791,760 — — — Total long-term debt $ 61,603,960 $ 291,949 $ 33,896,200 $ 260,149 Debt issuance costs are amortized over the life of the related debt. As of September 30, 2017 and 2016 , the Company also had an unamortized loss on the early retirement of debt of $1,941,182 and $2,055,369 , respectively, which has been deferred as a regulatory asset and is being amortized over a 20 year period. All of the debt agreements set forth certain representations, warranties and covenants to which the Company is subject, including financial covenants that limit Consolidated Long-Term Indebtedness to not more than 65% of total capitalization. All of the debt agreements except for the line-of-credit provide for priority indebtedness to not exceed 15% of consolidated total assets. On October 2, 2017, the Company issued 10 -year unsecured notes in the principal amount of $8,000,000 with a fixed interest rate of 3.58% per annum. The proceeds from the note were used to convert a portion of the Company's line-of-credit balance into longer-term financing. The aggregate annual maturities of long-term debt for the next five years ending after September 30, 2017 are as follows: Year Ending September 30 Maturities 2018 $ — 2019 17,791,760 2020 — 2021 6,312,200 2022 7,000,000 Thereafter 30,500,000 Total $ 61,603,960

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The details of income tax expense are as follows: Years Ended September 30 2017 2016 2015 Current income taxes: Federal $ 72,368 $ (1,216,745 ) $ 379,180 State 407,643 415,975 374,541 Total current income taxes 480,011 (800,770 ) 753,721 Deferred income taxes: Federal 3,129,925 4,302,906 2,289,729 State 195,454 164,048 127,112 Total deferred income taxes 3,325,379 4,466,954 2,416,841 Total income tax expense $ 3,805,390 $ 3,666,184 $ 3,170,562 Income tax expense for the years ended September 30, 2017 , 2016 and 2015 differed from amounts computed by applying the U.S. Federal income tax rate of 34% to earnings before income taxes due to the following: Years Ended September 30 2017 2016 2015 Income before income taxes $ 10,038,255 $ 9,473,050 $ 8,264,977 Income tax expense computed at the federal statutory rate $ 3,413,007 $ 3,220,837 $ 2,810,092 State income taxes, net of federal income tax benefit 398,044 382,815 331,091 Other, net (5,661 ) 62,532 29,379 Total income tax expense $ 3,805,390 $ 3,666,184 $ 3,170,562 The tax effects of temporary differences that give rise to the deferred tax assets and deferred tax liabilities are as follows: September 30 2017 2016 Deferred tax assets: Allowance for uncollectibles $ 37,752 $ 29,203 Accrued pension and postretirement medical benefits 1,747,429 2,532,672 Accrued vacation 239,414 262,273 Over-recovery of gas costs 545,894 345,318 Costs of gas held in storage 1,009,206 1,077,849 Deferred compensation 824,281 770,868 Other 348,833 340,121 Total gross deferred tax assets 4,752,809 5,358,304 Deferred tax liabilities: Utility plant 27,630,486 24,264,165 MVP investment 154,817 40,776 Other 44,354 11,217 Total gross deferred tax liabilities 27,829,657 24,316,158 Net deferred tax liability $ 23,076,848 $ 18,957,854 The current federal tax expense for fiscal 2016 reflected the effect of 50% bonus depreciation for the entire fiscal year 2016 as well as for nine months of fiscal 2015. The Protecting Americans from Tax Hikes (PATH Act), which extended 50% bonus depreciation for calendar 2015, was signed into law on December 18, 2015, subsequent to the issuance of the Company's September 30, 2015 annual report. As a result, $1,283,925 of deferred taxes that related to fiscal 2015 bonus depreciation were reflected in the fiscal 2016 tax provision, thereby reducing the current tax expense and increasing deferred tax expense by the same amount. The same situation occurred in fiscal 2014 when the extension of 50% bonus depreciation was not signed into law until December 19, 2014, following the issuance of the Company's financial statements for the year ended September 30, 2014. Correspondingly, fiscal 2015 income tax expense included the tax effect of the 50% bonus depreciation for fixed asset additions during the last nine months of fiscal 2014, which resulted in $1,442,211 in deferred tax expense related to fiscal 2014 being included in fiscal 2015. The recording of the effect of the adjustments for bonus depreciation had no effect on total income tax expense, net income or earnings per share. Only the current and deferred components of income tax expense and their corresponding assets and liabilities were affected. Under the PATH Act, 50% bonus depreciation extends through December 31, 2017, 40% for calendar 2018 and 30% for calendar 2019 with no provision for bonus depreciation after 2019. Virginia tax law does not recognize bonus depreciation; therefore, state income taxes were not impacted by the delayed bonus depreciation extensions. FASB ASC No. 740 - Income Taxes provides for the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recognized in the financial statements. The Company has evaluated its tax positions and accordingly has not identified any significant uncertain tax positions. The Company’s policy is to classify interest associated with uncertain tax positions as interest expense in the financial statements. Penalties are classified under other expense. The Company files a consolidated federal income tax return and state income tax returns in Virginia and West Virginia. The federal returns and the state returns for both Virginia and West Virginia for the tax years ended prior to September 30, 2014 are no longer subject to examination.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS The Company sponsors both a noncontributory defined benefit pension plan ("pension plan") and a postretirement benefit plan ("postretirement plan"). The pension plan covers substantially all employees and benefits fully vest after 5 years of credited service. Benefits paid to retirees are based on age at retirement, years of service and average compensation. In November 2016, the Board of Directors approved a "soft freeze" to the pension plan, whereby no employees hired on or after January 1, 2017 will be eligible to participate. Employees hired prior to January 1, 2017 will continue to participate in the plan and accrue benefits. The Board of Directors also approved an amendment to the 401(k) Plan which would allow for management to authorize a discretionary contribution to the 401(k) Plan for employees hired on or after January 1, 2017. This discretionary contribution would be determined each year, and if approved, would be applied to the eligible employees at the end of the calendar year. This Company contribution would be in addition to any employee elected deferrals and employer match as provided for under the 401(k) Plan. The postretirement benefit plan provides certain health care, supplemental retirement and life insurance benefits to retired employees who meet specific age and service requirements. Employees hired prior to January 1, 2000 are eligible to participate in the postretirement benefit plan. Employees must have a minimum of 10 years of service and retire after attaining the age of 55 in order to vest in the postretirement plan. Retiree contributions to the plan are based on the number of years of service to the Company as determined under the defined benefit plan. Employers who sponsor defined benefit plans must recognize the funded status of defined benefit pension and other postretirement plans as an asset or liability in their statements of financial position and recognize changes in that funded status in the year in which the changes occur through comprehensive income. For pension plans, the benefit obligation is the projected benefit obligation, and for other postretirement plans, the benefit obligation is the accumulated benefit obligation. The Company established a regulatory asset for the portion of the obligation expected to be recovered in rates in future periods. The regulatory asset is adjusted for the amortization of the transition obligation and recognition of actuarial gains and losses. The portion of the obligation attributable to the unregulated operations of the holding company is recognized in other comprehensive income. The following tables set forth the benefit obligation, fair value of plan assets, the funded status of the benefit plans, amounts recognized in the Company’s financial statements and the assumptions used. Pension Plan Postretirement Plan 2017 2016 2017 2016 Accumulated benefit obligation $ 25,481,993 $ 25,090,968 $ 17,666,812 $ 18,504,710 Change in benefit obligation: Benefit obligation at beginning of year $ 29,494,950 $ 27,167,621 $ 18,504,710 $ 15,355,668 Service cost 706,677 694,375 183,267 148,018 Interest cost 995,598 1,132,776 626,822 624,579 Actuarial (gain) loss (824,361 ) 2,440,957 (1,199,722 ) 2,812,516 Benefit payments, net of retiree contributions (715,517 ) (1,940,779 ) (448,265 ) (436,071 ) Benefit obligation at end of year $ 29,657,347 $ 29,494,950 $ 17,666,812 $ 18,504,710 Change in fair value of plan assets: Fair value of plan assets at beginning of year $ 23,113,057 $ 21,394,399 $ 11,122,783 $ 10,443,629 Actual return on plan assets, net of taxes 3,021,131 2,159,437 1,016,644 615,225 Employer contributions 1,000,000 1,500,000 1,000,000 500,000 Benefit payments, net of retiree contributions (715,517 ) (1,940,779 ) (448,265 ) (436,071 ) Fair value of plan assets at end of year $ 26,418,671 $ 23,113,057 $ 12,691,162 $ 11,122,783 Funded status $ (3,238,676 ) $ (6,381,893 ) $ (4,975,650 ) $ (7,381,927 ) Amounts recognized in the balance sheets consist of: Noncurrent liabilities $ (3,238,676 ) $ (6,381,893 ) $ (4,975,650 ) $ (7,381,927 ) Amounts recognized in accumulated other comprehensive loss: Net actuarial loss, net of tax $ 572,740 $ 1,583,345 $ 702,013 $ 913,886 Total amounts included in other comprehensive loss, net of tax $ 572,740 $ 1,583,345 $ 702,013 $ 913,886 Amounts deferred to a regulatory asset: Net actuarial loss $ 5,471,547 $ 6,732,800 $ 3,830,763 $ 5,563,642 Amounts recognized as regulatory assets $ 5,471,547 $ 6,732,800 $ 3,830,763 $ 5,563,642 During 2016, the Company offered a one-time, lump sum pay out option for vested, terminated employees not currently receiving payments under the pension plan. The lump sum offer was accepted by 40 of the 63 eligible participants. In September 2016, the pension plan distributed $1,241,529 to the participants electing to receive the lump sum payments, which resulted in a corresponding reduction of approximately $1,500,000 in the projected pension obligation. The Company expects that approximately $24,000 before tax, of accumulated other comprehensive income will be recognized as a reduction in net periodic benefit costs in fiscal 2018 and approximately $659,000 of amounts deferred as regulatory assets will be amortized and recognized in net periodic benefit costs in fiscal 2018. The following table details the actuarial assumptions used in determining the projected benefit obligations and net benefit cost of the pension and the accumulated benefit obligations and net benefit cost of the postretirement plan for 2017 , 2016 and 2015 . Pension Plan Postretirement Plan 2017 2016 2015 2017 2016 2015 Assumptions used to determine benefit obligations: Discount rate 3.72 % 3.42 % 4.22 % 3.69 % 3.33 % 4.15 % Expected rate of compensation increase 4.00 % 4.00 % 4.00 % N/A N/A N/A Assumptions used to determine benefit costs: Discount rate 3.42 % 4.22 % 4.22 % 3.33 % 4.15 % 4.10 % Expected long-term rate of return on plan assets 7.00 % 7.00 % 7.00 % 4.84 % 4.89 % 4.90 % Expected rate of compensation increase 4.00 % 4.00 % 4.00 % N/A N/A N/A To develop the expected long-term rate of return on assets assumption, the Company, with input from the plans' actuaries and investment advisors, considered the historical returns and the future expectations for returns for each asset class, as well as the target asset allocation of each plan’s portfolio. Components of net periodic benefit cost are as follows: Pension Plan Postretirement Plan 2017 2016 2015 2017 2016 2015 Service cost $ 706,677 $ 694,375 $ 654,782 $ 183,267 $ 148,018 $ 167,580 Interest cost 995,598 1,132,776 1,025,908 626,822 624,579 600,096 Expected return on plan assets (1,616,412 ) (1,492,241 ) (1,440,846 ) (571,513 ) (507,858 ) (516,656 ) Recognized loss 662,180 501,678 257,378 429,758 250,173 197,058 Net periodic benefit cost $ 748,043 $ 836,588 $ 497,222 $ 668,334 $ 514,912 $ 448,078 The assumed health care cost trend rates used in measuring the accumulated benefit obligation for the postretirement medical plan as of September 30, 2017 , 2016 and 2015 are presented below: Pre 65 Post 65 2017 2016 2015 2017 2016 2015 Health care cost trend rate assumed for next year 7.00 % 7.50 % 8.00 % 5.00 % 5.00 % 5.00 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 5.00 % 5.00 % 5.00 % 5.00 % 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate 2021 2021 2021 2017 2016 2015 The health care cost trend rate assumptions could have a significant effect on the amounts reported. A change of 1% would have the following effects: 1% Increase 1% Decrease Effect on total service and interest cost components $ 153,000 $ (121,000 ) Effect on accumulated postretirement benefit obligation 2,961,000 (2,385,000 ) The primary objectives of the Plan’s investment policy are to maintain investment portfolios that diversify risk through prudent asset allocation parameters, achieve asset returns that meet or exceed the plans’ actuarial assumptions, achieve asset returns that are competitive with like institutions employing similar investment strategies and meet expected future benefits in both the short-term and long-term. The investment policy provides for a range of investment allocations to allow for flexibility in responding to market conditions. The investment policy is periodically reviewed by the Company and a third-party investment advisor. The Company’s target and actual asset allocation in the pension and postretirement benefit plans as of September 30, 2017 and 2016 were: Pension Plan Postretirement Target 2017 2016 Target 2017 2016 Asset category: Equity securities 60 % 63 % 63 % 50 % 51 % 52 % Debt securities 40 % 36 % 36 % 50 % 48 % 47 % Cash — % 1 % 1 % — % 1 % — % Other — % — % — % — % — % 1 % The assets of the plans are invested in mutual funds. The Company uses the fair value hierarchy described in Note 1 to classify these assets. The mutual funds are included under Level 2 in the fair value hierarchy as their fair values are determined based on individual prices for each security that comprises the mutual funds. Most of the individual investments are determined based on quoted market prices for each security; however, certain fixed income securities and other investments are not actively traded and are valued based on similar investments. The following table contains the fair value classifications of the benefit plan assets: Defined Benefit Pension Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 265,100 $ 265,100 $ — $ — Common and Collective Trust and Pooled Funds: Bonds Liability Driven Investment 9,635,998 — 9,635,998 — Equities Domestic Large Cap Growth 5,068,282 — 5,068,282 — Domestic Large Cap Value 5,046,530 — 5,046,530 — Domestic Small/Mid Cap Core 2,393,221 — 2,393,221 — Foreign Large Cap Value 2,139,733 — 2,139,733 — Mutual Funds: Bonds Equities Foreign Large Cap Growth 399,909 — 399,909 — Foreign Large Cap Value 398,995 — 398,995 — Foreign Large Cap Core 1,070,903 — 1,070,903 — Total $ 26,418,671 $ 265,100 $ 26,153,571 $ — Defined Benefit Pension Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 117,265 $ 117,265 $ — $ — Common and Collective Trust and Pooled Funds: Bonds Domestic Fixed Income 4,497,373 — 4,497,373 — Equities Domestic Large Cap Growth 3,426,041 — 3,426,041 — Domestic Large Cap Value 4,543,385 — 4,543,385 — Domestic Small/Mid Cap Core 2,149,566 — 2,149,566 — Foreign Large Cap Value 1,795,897 — 1,795,897 — Mutual Funds: Bonds Domestic Fixed Income 3,615,209 — 3,615,209 — Foreign Fixed Income 234,622 — 234,622 — Equities Domestic Large Cap Growth 1,043,395 — 1,043,395 — Foreign Large Cap Growth 366,420 — 366,420 — Foreign Large Cap Value 373,480 — 373,480 — Foreign Large Cap Core 950,404 — 950,404 — Total $ 23,113,057 $ 117,265 $ 22,995,792 $ — Postretirement Benefit Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 64,616 $ 64,616 $ — $ — Mutual Funds Bonds Domestic Fixed Income 5,727,258 — 5,727,258 — Foreign Fixed Income 359,460 — 359,460 — Equities Domestic Large Cap Growth 1,998,971 — 1,998,971 — Domestic Large Cap Value 1,998,714 — 1,998,714 — Domestic Small/Mid Cap Growth 209,332 — 209,332 — Domestic Small/Mid Cap Value 209,630 — 209,630 — Domestic Small/Mid Cap Core 455,867 — 455,867 — Foreign Large Cap Growth 39,107 — 39,107 — Foreign Large Cap Value 1,079,766 — 1,079,766 — Foreign Large Cap Core 511,298 — 511,298 — Other 37,143 — 37,143 — Total $ 12,691,162 $ 64,616 $ 12,626,546 $ — Postretirement Benefit Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 43,455 $ 43,455 $ — $ — Mutual Funds Bonds Domestic Fixed Income 5,109,834 — 5,109,834 — Foreign Fixed Income 87,821 — 87,821 — Equities Domestic Large Cap Growth 1,824,796 — 1,824,796 — Domestic Large Cap Value 1,770,664 — 1,770,664 — Domestic Small/Mid Cap Growth 195,319 — 195,319 — Domestic Small/Mid Cap Value 198,884 — 198,884 — Domestic Small/Mid Cap Core 427,409 — 427,409 — Foreign Large Cap Value 964,827 — 964,827 — Foreign Large Cap Core 456,100 — 456,100 — Other 43,674 — 43,674 — Total $ 11,122,783 $ 43,455 $ 11,079,328 $ — Each mutual fund has been categorized based on its primary investment strategy. The Company expects to contribute $1,600,000 to its pension plan and $600,000 to its postretirement benefit plan in fiscal 2018. The following table reflects expected future benefit payments: Fiscal year ending September 30 Pension Postretirement 2018 $ 817,861 $ 618,241 2019 879,779 644,666 2020 966,930 671,228 2021 1,041,200 710,495 2022 1,139,637 749,674 2023-2027 6,981,849 4,148,403 The Company also sponsors a defined contribution plan (the “401k Plan”) covering all employees who elect to participate. Employees may contribute from 1% to 50% of their annual compensation to the 401k Plan, limited to a maximum annual amount as set periodically by the Internal Revenue Service. The Company matches 100% of the participant’s first 4% of contributions and 50% on the next 2% of contributions. Company matching contributions were $361,702 , $353,793 and $338,896 for 2017 , 2016 and 2015 , respectively.

Common Stock Options

Common Stock Options	12 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Common Stock Options	COMMON STOCK OPTIONS The Company’s stockholders approved the RGC Resources, Inc. Key Employee Stock Option Plan (“KESOP”). The KESOP provides for the issuance of common stock options to officers and certain other full-time salaried employees to acquire shares of the Company’s common stock. As of September 30, 2017 , the number of shares available for future grants was 36,000 . FASB ASC No. 718 - Compensation - Stock Compensation requires that compensation expense be recognized for the issuance of equity instruments to employees. During the fiscal years ended 2017 , 2016 and 2015 , the Board approved stock option grants to certain officers. As required by the KESOP, each option's exercise price per share equaled the fair value of the Company's common stock on the grant date. Pursuant to the Plan, the options vest over a six -month period and are exercisable over a ten -year period from the date of issuance. As the Company's stock options are not traded on the open market, the fair value of each grant is estimated on the date of grant using the Black-Scholes option pricing model including the following assumptions: Years Ended September 30, 2017 2016 2015 Expected volatility 26.09% 28.78% 34.34% Expected dividends 3.81% 3.99% 4.11% Expected exercise term (years) 7.00 7.00 7.00 Risk-free interest rate 2.20% 2.10% 1.98% The underlying methods regarding each assumption are as follows: Expected volatility is based on the historical volatilities of the daily closing price of the Company's common stock. Expected dividend rate is based on historical dividend payout trends. Expected exercise term is based on the average time historical option grants were outstanding before being exercised. Risk-free interest rate is based on the 7 -year Treasury rate on the date of option grant. Forfeitures are recognized when they occur. Stock option transactions under the Company's plans for the years ended September 30, 2017 , 2016 and 2015 are summarized below. The information contained in the tables below have been restated to reflect the effect of the stock split: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Terms (years) Aggregate Intrinsic Value 1 Options outstanding, September 30, 2014 57,000 $ 12.65 8.8 $ 34,840 Options granted 25,500 14.40 Options exercised (3,900 ) 12.66 Options expired — — Options forfeited — — Options outstanding, September 30, 2015 78,600 13.22 8.3 43,086 Options granted 24,000 14.15 Options exercised (3,300 ) 12.65 Options expired — — Options forfeited (12,000 ) 13.20 Options outstanding, September 30, 2016 87,300 13.50 7.8 200,211 Options granted 25,500 16.37 Options exercised (11,225 ) 12.67 Options expired — — Options forfeited — — Options outstanding, September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 Vested and exercisable at September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 1 Aggregate intrinsic value includes only those options where the exercise price is below the market price. Years Ended September 30, 2017 2016 2015 Weighted-average grant date option fair value $ 2.89 $ 2.69 $ 3.28 Stock option expense 73,780 64,640 83,640 Intrinsic value of options exercised 99,929 8,418 5,624 Proceeds from exercise of stock options 142,241 41,762 49,366 OTHER STOCK PLANS Dividend Reinvestment and Stock Purchase Plan The Company offers a Dividend Reinvestment and Stock Purchase Plan (the “DRIP”) to shareholders of record for the reinvestment of dividends and the purchase of up to $40,000 per year in additional shares of common stock of the Company. Under the DRIP, the Company issued 36,446 , 52,146 and 12,647 shares in 2017 , 2016 and 2015 , respectively. As of September 30, 2017 , the Company had 448,973 shares of stock available for issuance under the DRIP. Restricted Stock Plan for Outside Directors The Board of Directors of the Company implemented the Restricted Stock Plan for Outside Directors (the “Plan”) effective January 27, 1997. Under the Plan, a minimum of 40% of the monthly retainer fee paid to each non-employee director of Resources was paid in shares of common stock (“Restricted Stock”). The number of shares of Restricted Stock awarded each month is determined based on the closing sales price of Resources' common stock on the NASDAQ Global Market on the first business day of the month. The Restricted Stock issued under the Plan vests only in the case of a participant's death, disability, retirement, or in the event of a change in control of Resources. The Restricted Stock may not be sold, transferred, assigned or pledged by the participant until the shares have vested under the terms of the Plan. The shares of Restricted Stock will be forfeited to Resources by a participant's voluntary resignation during his or her term on the Board or removal for cause as a director. Effective October 1, 2016, the Board of Directors amended the Plan to remove the requirement that directors take a minimum 40% of their retainer in Restricted Stock for those directors who owned at least 10,000 shares of Resources stock. The Company assumes all directors will complete their term and there will be no forfeiture of the Restricted Stock. Since the inception of the Plan, no director has forfeited any shares of Restricted Stock. The Company recognizes as compensation the market value of the Restricted Stock in the period it is issued. The following table reflects the director compensation activity pursuant to the Plan: 2017 2016 2015 Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Beginning of year balance 107,023 $ 10.11 100,373 $ 9.80 94,267 $ 9.53 Granted 4,870 16.77 6,650 14.79 6,106 13.92 Vested — — — — — — Forfeited — — — — — — End of year balance 111,893 $ 10.56 107,023 $ 10.11 100,373 $ 9.80 The fair market value of the Restricted Stock issued as compensation during fiscal 2017 , 2016 and 2015 was $99,400 , $98,334 and $85,000 . No Restricted Stock vested or was forfeited during fiscal 2017 , 2016 and 2015 . As of September 30, 2017 , the Company had 85,233 shares available for issuance under the Plan. RGC Resources, Inc. Restricted Stock Plan The Board of Directors of the Company implemented the RGC Resources, Inc. Restricted Stock Plan (the “Restricted Stock Plan”) in 2017 following approval by the shareholders at the Company's annual meeting held on February 6, 2017. Under the Restricted Stock Plan, the Compensation Committee of the Board of Directors may grant shares of restricted stock that vest over time to key employees and officers for the purpose of attracting and retaining those individuals essential to the operation and growth of the Company. The Restricted Stock Plan provides for certain restrictions and non-transferability requirements until minimum levels of ownership are obtained. Such restrictions may continue beyond the vesting period. The Restricted Stock Plan originally authorized 300,000 shares to be available for issuance; however, following the three-for-two stock split on March 1, 2017, the total authorized shares increased to 450,000 . As of September 30, 2017, no shares have been granted under the Restricted Stock Plan. Stock Bonus Plan Under the Stock Bonus Plan, executive officers are encouraged to own a position in the Company’s common stock of at least 50% of the value of their annual salary. To promote this policy, the Plan provides that all officers with stock ownership positions below 50% of the value of their annual salaries must, unless approved by the Committee, use no less than 50% of any performance bonus to purchase Company common stock. Shares from the Stock Bonus Plan may also be issued to certain employees and management personnel in recognition of their performance and service. Under the Stock Bonus Plan, the Company issued 1,628 , 2,813 and 4,097 shares valued at $30,154 , $39,819 and $59,332 , respectively, in 2017 , 2016 and 2015 . As of September 30, 2017 the Company had 4,785 shares of stock available for issuance under the Stock Bonus Plan.

Other Stock Plans

Other Stock Plans	12 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Other Stock Plans	COMMON STOCK OPTIONS The Company’s stockholders approved the RGC Resources, Inc. Key Employee Stock Option Plan (“KESOP”). The KESOP provides for the issuance of common stock options to officers and certain other full-time salaried employees to acquire shares of the Company’s common stock. As of September 30, 2017 , the number of shares available for future grants was 36,000 . FASB ASC No. 718 - Compensation - Stock Compensation requires that compensation expense be recognized for the issuance of equity instruments to employees. During the fiscal years ended 2017 , 2016 and 2015 , the Board approved stock option grants to certain officers. As required by the KESOP, each option's exercise price per share equaled the fair value of the Company's common stock on the grant date. Pursuant to the Plan, the options vest over a six -month period and are exercisable over a ten -year period from the date of issuance. As the Company's stock options are not traded on the open market, the fair value of each grant is estimated on the date of grant using the Black-Scholes option pricing model including the following assumptions: Years Ended September 30, 2017 2016 2015 Expected volatility 26.09% 28.78% 34.34% Expected dividends 3.81% 3.99% 4.11% Expected exercise term (years) 7.00 7.00 7.00 Risk-free interest rate 2.20% 2.10% 1.98% The underlying methods regarding each assumption are as follows: Expected volatility is based on the historical volatilities of the daily closing price of the Company's common stock. Expected dividend rate is based on historical dividend payout trends. Expected exercise term is based on the average time historical option grants were outstanding before being exercised. Risk-free interest rate is based on the 7 -year Treasury rate on the date of option grant. Forfeitures are recognized when they occur. Stock option transactions under the Company's plans for the years ended September 30, 2017 , 2016 and 2015 are summarized below. The information contained in the tables below have been restated to reflect the effect of the stock split: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Terms (years) Aggregate Intrinsic Value 1 Options outstanding, September 30, 2014 57,000 $ 12.65 8.8 $ 34,840 Options granted 25,500 14.40 Options exercised (3,900 ) 12.66 Options expired — — Options forfeited — — Options outstanding, September 30, 2015 78,600 13.22 8.3 43,086 Options granted 24,000 14.15 Options exercised (3,300 ) 12.65 Options expired — — Options forfeited (12,000 ) 13.20 Options outstanding, September 30, 2016 87,300 13.50 7.8 200,211 Options granted 25,500 16.37 Options exercised (11,225 ) 12.67 Options expired — — Options forfeited — — Options outstanding, September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 Vested and exercisable at September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 1 Aggregate intrinsic value includes only those options where the exercise price is below the market price. Years Ended September 30, 2017 2016 2015 Weighted-average grant date option fair value $ 2.89 $ 2.69 $ 3.28 Stock option expense 73,780 64,640 83,640 Intrinsic value of options exercised 99,929 8,418 5,624 Proceeds from exercise of stock options 142,241 41,762 49,366 OTHER STOCK PLANS Dividend Reinvestment and Stock Purchase Plan The Company offers a Dividend Reinvestment and Stock Purchase Plan (the “DRIP”) to shareholders of record for the reinvestment of dividends and the purchase of up to $40,000 per year in additional shares of common stock of the Company. Under the DRIP, the Company issued 36,446 , 52,146 and 12,647 shares in 2017 , 2016 and 2015 , respectively. As of September 30, 2017 , the Company had 448,973 shares of stock available for issuance under the DRIP. Restricted Stock Plan for Outside Directors The Board of Directors of the Company implemented the Restricted Stock Plan for Outside Directors (the “Plan”) effective January 27, 1997. Under the Plan, a minimum of 40% of the monthly retainer fee paid to each non-employee director of Resources was paid in shares of common stock (“Restricted Stock”). The number of shares of Restricted Stock awarded each month is determined based on the closing sales price of Resources' common stock on the NASDAQ Global Market on the first business day of the month. The Restricted Stock issued under the Plan vests only in the case of a participant's death, disability, retirement, or in the event of a change in control of Resources. The Restricted Stock may not be sold, transferred, assigned or pledged by the participant until the shares have vested under the terms of the Plan. The shares of Restricted Stock will be forfeited to Resources by a participant's voluntary resignation during his or her term on the Board or removal for cause as a director. Effective October 1, 2016, the Board of Directors amended the Plan to remove the requirement that directors take a minimum 40% of their retainer in Restricted Stock for those directors who owned at least 10,000 shares of Resources stock. The Company assumes all directors will complete their term and there will be no forfeiture of the Restricted Stock. Since the inception of the Plan, no director has forfeited any shares of Restricted Stock. The Company recognizes as compensation the market value of the Restricted Stock in the period it is issued. The following table reflects the director compensation activity pursuant to the Plan: 2017 2016 2015 Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Beginning of year balance 107,023 $ 10.11 100,373 $ 9.80 94,267 $ 9.53 Granted 4,870 16.77 6,650 14.79 6,106 13.92 Vested — — — — — — Forfeited — — — — — — End of year balance 111,893 $ 10.56 107,023 $ 10.11 100,373 $ 9.80 The fair market value of the Restricted Stock issued as compensation during fiscal 2017 , 2016 and 2015 was $99,400 , $98,334 and $85,000 . No Restricted Stock vested or was forfeited during fiscal 2017 , 2016 and 2015 . As of September 30, 2017 , the Company had 85,233 shares available for issuance under the Plan. RGC Resources, Inc. Restricted Stock Plan The Board of Directors of the Company implemented the RGC Resources, Inc. Restricted Stock Plan (the “Restricted Stock Plan”) in 2017 following approval by the shareholders at the Company's annual meeting held on February 6, 2017. Under the Restricted Stock Plan, the Compensation Committee of the Board of Directors may grant shares of restricted stock that vest over time to key employees and officers for the purpose of attracting and retaining those individuals essential to the operation and growth of the Company. The Restricted Stock Plan provides for certain restrictions and non-transferability requirements until minimum levels of ownership are obtained. Such restrictions may continue beyond the vesting period. The Restricted Stock Plan originally authorized 300,000 shares to be available for issuance; however, following the three-for-two stock split on March 1, 2017, the total authorized shares increased to 450,000 . As of September 30, 2017, no shares have been granted under the Restricted Stock Plan. Stock Bonus Plan Under the Stock Bonus Plan, executive officers are encouraged to own a position in the Company’s common stock of at least 50% of the value of their annual salary. To promote this policy, the Plan provides that all officers with stock ownership positions below 50% of the value of their annual salaries must, unless approved by the Committee, use no less than 50% of any performance bonus to purchase Company common stock. Shares from the Stock Bonus Plan may also be issued to certain employees and management personnel in recognition of their performance and service. Under the Stock Bonus Plan, the Company issued 1,628 , 2,813 and 4,097 shares valued at $30,154 , $39,819 and $59,332 , respectively, in 2017 , 2016 and 2015 . As of September 30, 2017 the Company had 4,785 shares of stock available for issuance under the Stock Bonus Plan.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Long-Term Contracts Due to the nature of the natural gas distribution business, the Company enters into agreements with both suppliers and pipelines to contract for natural gas commodity purchases, storage capacity and pipeline delivery capacity. The Company obtains most of its regulated natural gas supply through an asset management contract between Roanoke Gas and a third party asset manager. The Company utilizes an asset manager to optimize the use of its transportation, storage rights, and gas supply inventories which helps to ensure a secure and reliable source of natural gas. Under the current asset management contract, the Company has designated the asset manager to act as agent for the Company's storage capacity and all gas balances in storage. The Company retains ownership of gas in storage. Under provisions of this contract, the Company is obligated to purchase its winter storage requirements from the asset manager during the spring and summer injection periods at market price. The table below details the volumetric obligations as of September 30, 2017 for the remainder of the contract period. The current asset management contract will expire in March 2018. Year Natural Gas Contracts 2017-2018 369,828 Total 369,828 The Company also has contracts for pipeline and storage capacity which extend for various periods. These capacity costs and related fees are valued at tariff rates in place as of September 30, 2017 . These rates may increase or decrease in the future based upon rate filings and rate orders granting a rate change to the pipeline or storage operator. Roanoke Gas expended approximately $28,496,000 , $24,852,000 and $33,405,000 under the asset management, pipeline and storage contracts in fiscal years 2017 , 2016 and 2015 , respectively. The table below details the pipeline and storage capacity obligations as of September 30, 2017 for the remainder of the contract period. Year Pipeline and 2017-2018 $ 11,232,436 2018-2019 10,113,115 2019-2020 7,633,155 2020-2021 5,221,751 2021-2022 4,565,743 Thereafter 3,067,053 Total $ 41,833,253 Other Contracts The Company maintains other agreements in the ordinary course of business covering various lease, maintenance, equipment and service contracts. These agreements currently extend through December 2031 and are not material to the Company. Legal From time to time, the Company may become involved in litigation or claims arising out of its operations in the normal course of business. At the current time, the Company is not known to be a party to any legal proceedings that would be expected to have a materially adverse impact on its financial position, results of operations or cash flows. Environmental Matters Both Roanoke Gas and a previously owned gas subsidiary operated manufactured gas plants (MGPs) as a source of fuel for lighting and heating until the early 1950’s. A by-product of operating MGPs was coal tar, and the potential exists for tar waste contaminants at the former plant sites. While the Company does not currently recognize any commitments or contingencies related to environmental costs at either site, should the Company ever be required to remediate either site, it will pursue all prudent and reasonable means to recover any related costs, including the use of insurance claims and regulatory approval for rate case recognition of expenses associated with any work required.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The following table summarizes the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and the fair value measurements by level within the fair value hierarchy as defined in Note 1 as of September 30, 2017 and 2016 , respectively: Fair Value Measurements - September 30, 2017 Fair Value Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ 116,843 $ — $ 116,843 $ — Total $ 116,843 $ — $ 116,843 $ — Liabilities: Natural gas purchases $ 805,159 $ — $ 805,159 $ — Total $ 805,159 $ — $ 805,159 $ — Fair Value Measurements - September 30, 2016 Fair Value Quoted Prices in Significant Other Significant Liabilities: Natural gas purchases $ 1,052,930 $ — $ 1,052,930 $ — Total $ 1,052,930 $ — $ 1,052,930 $ — Under the asset management contract, a timing difference can exist between the payment for natural gas purchases and the actual receipt of such purchases. Payments are made based on a predetermined monthly volume with the price based on the weighted average first of the month index prices corresponding to the month of the scheduled payment. At September 30, 2017 and 2016 , the Company had recorded in accounts payable the estimated fair value of the liability determined on the corresponding first of month index prices for which the liability was expected to be settled. The Company’s nonfinancial assets and liabilities that are measured at fair value on a nonrecurring basis consist of its asset retirement obligations. The asset retirement obligations are measured at fair value at initial recognition based on expected future cash flows to settle the obligation. The carrying value of cash and cash equivalents, accounts receivable, borrowings under line-of-credit, accounts payable (with the exception of the timing difference under the asset management contract), customer credit balances and customer deposits is a reasonable estimate of fair value due to the shorter-term nature of these financial instruments. The following table summarizes the fair value of the Company’s financial assets and liabilities that are not adjusted to fair value in the financial statements as of September 30, 2017 and 2016 . Fair Value Measurements - September 30, 2017 Carrying Quoted Prices in Significant Other Significant Liabilities: Long-term debt $ 43,812,200 $ — $ — $ 45,689,238 Total $ 43,812,200 $ — $ — $ 45,689,238 Fair Value Measurements - September 30, 2016 Carrying Quoted Prices in Significant Other Significant Liabilities: Long-term debt $ 33,896,200 $ — $ — $ 36,163,523 Total $ 33,896,200 $ — $ — $ 36,163,523 The fair value of long-term debt for Roanoke Gas is estimated by discounting the future cash flows of the fixed rate debt based on the underlying 20 -year Treasury rate and estimated credit spread extrapolated based on market conditions since the issuance of the debt. A 64 basis point increase in the 20 -year Treasury in fiscal 2017 partially offset by a reduction in the assumed credit spreads accounted for the smaller differential between the fair value and the carrying amount of the notes payable at the end of the year. The fair value for the RGC Midstream debt is estimated by discounting the estimated credit spread extrapolated based on market conditions. FASB ASC 825 – Financial Instruments requires disclosures regarding concentrations of credit risk from financial instruments. Cash equivalents are investments in high-grade, short-term securities (original maturity less than three months), placed with financially sound institutions. Accounts receivable are from a diverse group of customers including individuals and small and large companies in various industries. The Company maintains certain credit standards with its customers and requires a customer deposit if such evaluation warrants.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Sep. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	QUARTERLY FINANCIAL INFORMATION (UNAUDITED) Quarterly financial data for the years ended September 30, 2017 and 2016 is summarized as follows: 2017 First Second Third Fourth Operating revenues $ 18,788,585 $ 21,900,013 $ 11,435,824 $ 10,172,448 Gross margin $ 9,390,905 $ 10,829,730 $ 6,634,402 $ 5,954,120 Operating income $ 3,982,275 $ 5,589,207 $ 1,328,207 $ 766,620 Net income $ 2,232,218 $ 3,225,199 $ 615,562 $ 159,886 Earnings per share of common stock: Basic $ 0.31 $ 0.45 $ 0.09 $ 0.02 Diluted $ 0.31 $ 0.45 $ 0.08 $ 0.02 2016 First Second Third Fourth Operating revenues $ 16,010,056 $ 21,777,773 $ 11,295,197 $ 9,980,265 Gross margin $ 8,738,116 $ 10,649,269 $ 6,312,340 $ 5,865,189 Operating income $ 3,498,052 $ 5,444,314 $ 1,453,350 $ 816,376 Net income $ 1,922,790 $ 3,111,447 $ 627,068 $ 145,561 Earnings per share of common stock: Basic $ 0.27 $ 0.44 $ 0.09 $ 0.02 Diluted $ 0.27 $ 0.44 $ 0.09 $ 0.02

Subsequent Events

Subsequent Events	12 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On October 2, 2017, Roanoke Gas entered into two 10 -year unsecured notes with Prudential Investment Management in the total principal amount of $8,000,000 . The notes have an annual interest rate of 3.58% . The proceeds from the note will be used to convert a portion of the Company's line-of-credit balance into longer-term financing. The Company has evaluated subsequent events through the date the financial statements were issued. There were no other items not otherwise disclosed which would have materially impacted the Company’s consolidated financial statements.

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation —RGC Resources, Inc. is an energy services company primarily engaged in the sale and distribution of natural gas. The consolidated financial statements include the accounts of RGC Resources, Inc. and its wholly owned subsidiaries (“Resources” or the “Company”): Roanoke Gas Company (“Roanoke Gas”); Diversified Energy Company; RGC Ventures of Virginia, Inc., operating as Application Resources and The Utility Consultants; and RGC Midstream, LLC. Roanoke Gas is a natural gas utility, which distributes and sells natural gas to approximately 59,800 residential, commercial and industrial customers within its service areas in Roanoke, Virginia and the surrounding localities. The Company’s business is seasonal in nature as a majority of natural gas sales are for space heating during the winter season. Roanoke Gas is regulated by the Virginia State Corporation Commission (“SCC” or “Virginia Commission”). RGC Ventures of Virginia, Inc. was dissolved in 2016 after Application Resources, which provided information system services to software providers in the utility industry, ceased operations in 2016, and The Utility Consultants, which provided regulatory consulting services to other utilities, ceased operations in 2015. RGC Midstream, LLC is a wholly-owned subsidiary created in 2015 to invest in the Mountain Valley pipeline project. Diversified Energy Company is currently inactive. The Company follows accounting and reporting standards established by the Financial Accounting Standards Board (“FASB”) and the Securities and Exchange Commission (“SEC”). Resources has only one reportable segment as defined under FASB ASC No. 280 – Segment Reporting . All intercompany transactions have been eliminated in consolidation.
Rate Regulated Basis of Accounting	Rate Regulated Basis of Accounting —The Company’s regulated operations follow the accounting and reporting requirements of FASB ASC No. 980, Regulated Operations . The economic effects of regulation can result in a regulated company deferring costs that have been or are expected to be recovered from customers in a period different from the period in which the costs would be charged to expense by an unregulated enterprise. When this situation occurs, costs are deferred as assets in the consolidated balance sheet (regulatory assets) and recorded as expenses when such amounts are reflected in rates. Additionally, regulators can impose liabilities upon a regulated company for amounts previously collected from customers and for current collection in rates of costs that are expected to be incurred in the future (regulatory liabilities). In the event the provisions of FASB ASC No. 980 no longer apply to any or all regulatory assets or liabilities, the Company would write off such amounts and include them in the consolidated statements of income and comprehensive income in the period for which FASB ASC No. 980 no longer applied.
Utility Plant and Depreciation	Utility Plant and Depreciation —Utility plant is stated at original cost and includes direct labor and materials, contractor costs, and all allocable overhead charges. The Company applies the group method of accounting, where the costs of like assets are aggregated and depreciated by applying a rate based on the average expected useful life of the assets. In accordance with Company policy, expenditures for depreciable assets with a life greater than one year are capitalized, along with any upgrades or improvements to existing assets, when they significantly improve or extend the original expected useful life of an asset. Expenditures for maintenance, repairs, and minor renewals and betterments are expensed as incurred. The original cost of depreciable property retired is removed from utility plant and charged to accumulated depreciation. The cost of asset removals, less salvage, is charged to “regulatory cost of retirement obligations” or “asset retirement obligations” as explained under Asset Retirement Obligations below. Utility plant is composed of the following major classes of assets: Years Ended September 30 2017 2016 Distribution and transmission $ 177,845,619 $ 160,354,300 LNG storage 13,299,288 12,594,294 General and miscellaneous 13,078,807 12,628,692 Total utility plant in service $ 204,223,714 $ 185,577,286 Provisions for depreciation are computed principally at composite straight-line rates over periods ranging from 5 to 76 years . Rates are determined by depreciation studies which are required to be performed at least every 5 years on the regulated utility assets of Roanoke Gas. The Company completed its last depreciation study in June 2014. The composite weighted-average depreciation rate realized using the most recently completed depreciation study was 3.29% for the fiscal year ended September 30, 2017 and 3.25% for the fiscal years ended September 30, 2016 and 2015. The composite rates are composed of two components, one based on average service life and one based on cost of retirement. As a result, the Company accrues the estimated cost of retirement of long-lived assets through depreciation expense. Retirement costs are not a legal obligation but rather the result of cost-based regulation and are accounted for under the provisions of FASB ASC No. 980. Such amounts are classified as a regulatory liability. The Company reviews long-lived assets and certain identifiable intangibles for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. These reviews have not identified any impairments which would have a material effect on the results of operations or financial condition.
Asset Retirement Obligations	Asset Retirement Obligations —FASB ASC No. 410, Asset Retirement and Environmental Obligations , requires entities to record the fair value of a liability for an asset retirement obligation when there exists a legal obligation for the retirement of the asset. When the liability is initially recorded, the entity capitalizes the cost, thereby increasing the carrying amount of the underlying asset. In subsequent periods, the liability is accreted, and the capitalized cost is depreciated over the useful life of the underlying asset. The Company has recorded asset retirement obligations for its future legal obligations related to purging and capping its distribution mains and services upon retirement, although the timing of such retirements is uncertain. The Company’s composite depreciation rates include a component to provide for the cost of retirement of assets. As a result, the Company accrues the estimated cost of retirement of its utility plant through depreciation expense and creates a corresponding regulatory liability. The costs of retirement considered in the development of the depreciation component include those costs associated with the legal liability. Therefore, the asset retirement obligation is reclassified from the regulatory cost of retirement obligation. If the legal obligations were to exceed the regulatory liability provided for in the depreciation rates, the Company would establish a regulatory asset for such difference with the anticipation of future recovery through rates charged to customers. In 2017, the Company increased its asset retirement obligation to reflect revisions to the estimated cash flows for asset retirements.
Cash, Cash Equivalents and Short-Term Investments	Cash, Cash Equivalents and Short-Term Investments —From time to time, the Company will have balances on deposit at banks in excess of the amount insured by the Federal Deposit Insurance Corporation (“FDIC”). The Company has not experienced any losses on these accounts and does not consider these amounts to be at credit risk. As of September 30, 2017 , the Company did not have any bank deposits in excess of the FDIC insurance limits. For purposes of the consolidated statements of cash flows, the Company considers all highly liquid debt instruments purchased with an original maturity of three months or less to be cash equivalents.
Customer Receivables and Allowance for Doubtful Accounts	Customer Receivables and Allowance for Doubtful Accounts —Accounts receivable include amounts billed to customers for natural gas sales and related services and gas sales occurring subsequent to normal billing cycles but before the end of the period. The Company provides an estimate for losses on these receivables by utilizing historical information, current account balances, account aging and current economic conditions. Customer accounts are charged off annually when deemed uncollectible or when turned over to a collection agency for action.
Financing Receivables	Financing Receivables —Financing receivables represent a contractual right to receive money either on demand or on fixed or determinable dates and are recognized as assets on the entity’s balance sheet. Trade receivables are the Company's one primary type of financing receivables, resulting from the sale of natural gas and other services to its customers. These receivables are short-term in nature with a provision for uncollectible balances included in the financial statements.
Inventories	Inventories —Inventories, consisting of natural gas in storage and materials and supplies, are recorded at average cost. Injections into storage are priced at the purchase cost at the time of injection and withdrawals from storage are priced at the weighted average price in storage. Materials and supplies are removed from inventory at average cost.
Unbilled Revenues	Unbilled Revenues —The Company bills its natural gas customers on a monthly cycle; however, the billing cycle period for most customers does not coincide with the accounting periods used for financial reporting. As the Company recognizes revenue when gas is delivered, an accrual is made to estimate revenues for natural gas delivered to customers but not billed during the accounting period.
Income Taxes	Income Taxes —Income taxes are accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the years in which those temporary differences are expected to be recovered or settled. A valuation allowance against deferred tax assets is provided if it is more likely than not the deferred tax asset will not be realized. The Company and its subsidiaries file state and federal consolidated income tax returns.
Debt Expenses	Debt Expenses —Debt issuance expenses are deferred and amortized over the lives of the debt instruments. The unamortized balances are offset against the carrying value of long-term debt.
Over/Under-Recovery of Natural Gas Costs	Over/Under-Recovery of Natural Gas Costs —Pursuant to the provisions of the Company’s Purchased Gas Adjustment (“PGA”) clause, the SCC provides the Company with a method of passing along to its customers increases or decreases in natural gas costs incurred by its regulated operations, including gains and losses on natural gas derivative hedging instruments. On a quarterly basis, the Company files a PGA rate adjustment request with the SCC to adjust the gas cost component of its rates up or down depending on projected price and activity. Once administrative approval is received, the Company adjusts the gas cost component of its rates to reflect the approved amount. As actual costs will differ from the projections used in establishing the PGA rate, the Company may either over-recover or under-recover its actual gas costs during the period. Any difference between actual costs incurred and costs recovered through the application of the PGA is recorded as a regulatory asset or liability. At the end of the deferral period, the balance of the net deferred charge or credit is amortized over an ensuing 12 -month period as amounts are reflected in customer billings.
Fair Value	Fair Value —Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The Company determines fair value based on the following fair value hierarchy which prioritizes each input to the valuation methods into one of the following three broad levels: • Level 1 – Unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. • Level 2 – Inputs other than quoted prices in Level 1 that are either for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3 – Unobservable inputs for the asset or liability where there is little, if any, market activity which require the Company to develop its own assumptions. The fair value hierarchy gives the highest priority to unadjusted quoted prices in active markets (Level 1) and the lowest priority to unobservable inputs (Level 3). All fair value disclosures are categorized within one of the three categories in the hierarchy. See fair value disclosures below and in Notes 8 and 12.
Use of Estimates	Use of Estimates —The preparation of financial statements in conformity with Generally Accepted Accounting Principles in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Excise and Sales Taxes	Excise and Sales Taxes —Certain excise and sales taxes imposed by the state and local governments in the Company’s service territory are collected by the Company from its customers. These taxes are accounted for on a net basis and therefore are not included as revenues in the Company’s Consolidated Statements of Income.
Earnings Per Share	Earnings Per Share —Basic earnings per share and diluted earnings per share are calculated by dividing net income by the weighted-average common shares outstanding during the period and the weighted-average common shares outstanding during the period plus dilutive potential common shares, respectively. Dilutive potential common shares are calculated in accordance with the treasury stock method, which assumes that proceeds from the exercise of all options are used to repurchase common stock at market value. The amount of shares remaining after the proceeds are exhausted represents the potentially dilutive effect of the securities.
Business and Credit Concentrations	Business and Credit Concentrations — The primary business of the Company is the distribution of natural gas to residential, commercial and industrial customers in its service territories. No sales to individual customers accounted for more than 5% of total revenue in any period or amounted to more than 5% of total accounts receivable. Roanoke Gas currently holds the only franchises and certificates of public convenience and necessity to distribute natural gas in its service area. These franchises are effective through January 1, 2036 . The Company's current certificates of public convenience and necessity in Virginia are exclusive and are intended for perpetual duration. Roanoke Gas is served directly by two primary pipelines that provide all of the natural gas supplied to the Company’s customers. Depending upon weather conditions and the level of customer demand, failure of one or both of these transmission pipelines could have a major adverse impact on the Company.
Derivative and Hedging Activities	Derivative and Hedging Activities —FASB ASC No. 815, Derivatives and Hedging , requires the recognition of all derivative instruments as assets or liabilities in the Company’s balance sheet and measurement of those instruments at fair value. The Company’s hedging and derivatives policy allows management to enter into derivatives for the purpose of managing the commodity and financial market risks of its business operations. The Company’s hedging and derivatives policy specifically prohibits the use of derivatives for speculative purposes. The key market risks that RGC Resources, Inc. hedges against include the price of natural gas and the cost of borrowed funds. The Company historically has entered into collars, swaps and caps for the purpose of hedging the price of natural gas in order to provide price stability during the winter months. The fair value of these instruments is recorded in the balance sheet with the offsetting entry to either under-recovery of gas costs or over-recovery of gas costs. Net income and other comprehensive income are not affected by the change in market value as any cost incurred or benefit received from these instruments is recoverable or refunded through the PGA as the SCC allows for full recovery of prudent costs associated with natural gas purchases.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards	Recently Adopted Accounting Standards —In November 2015, the FASB issued ASU 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes . The ASU requires that all deferred tax assets and liabilities be presented as noncurrent and eliminates prior guidance to classify and present deferred tax assets and liabilities as current and noncurrent. This ASU is effective for the Company for the annual reporting period ended September 30, 2018 and interim periods within that annual period. Early application is permitted. The Company adopted this ASU for the quarter ended December 31, 2015. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting . The guidance simplifies several aspects of the accounting for share-based payment award transactions, including income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The new guidance is effective for the Company for the annual reporting period ending September 30, 2018 and interim periods within that annual period. Early adoption is permitted. The Company adopted this ASU for the quarter ended September 30, 2016. Under the prior guidance, excess tax benefits were to be tracked in an APIC pool and not recognized in the income statement. Tax deficiencies were netted against the accumulated APIC pool and only recognized in the income statement starting at the time tax deficiencies exceeded the pool. Under ASU 2016-09, the APIC pool is eliminated with all excess tax benefits and deficiencies recognized in income tax expense on the income statement. Prior to the adoption of this ASU, stock option activity did not result in the accumulation of an APIC pool; therefore, adopting the ASU had minimal impact on the Company’s current financial position, results of operations or cash flows and no impact on prior results. In January 2017, the FASB issued ASU 2017-03, Accounting Changes and Error Corrections and Investments - Equity Method and Joint Ventures . This update adds the text of the SEC Staff Announcement, Disclosure of the Impact That Recently Issued Accounting Standards Will Have on the Financial Statements of a Registrant When Such Standards Are Adopted in a Future Period (in accordance with Staff Accounting Bulletin Topic 11.M) as paragraph 250-10-S99-6. Related specifically to ASU 2014-09, ASU 2016-02 and ASU 2016-13, an SEC registrant should evaluate ASUs that have not yet been adopted to determine and include appropriate financial disclosures and MD&A discussions, including consideration of additional qualitative disclosures, to assist financial statement readers in assessing the significance of impact on adoption. The new guidance is effective immediately. The nature of this guidance relates to the effectiveness and quality of disclosures related to ASUs not yet adopted; however, there is no effect on the Company's financial position, results of operations or cash flows. Recently Issued Accounting Standards —In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) that affects any entity that enters into contracts with customers for the transfer of goods or services or transfer of non-financial assets. This guidance supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. The core principle of the new guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contract with the customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when, or as, the entity satisfies the performance obligation. In August 2015, the FASB issued ASU 2015-14 that deferred the effective date of this guidance by one year making the standard effective for the Company's annual reporting period ending September 30, 2019 and interim periods within that annual period. The FASB continues to issue subsequent guidance under ASC No. 606 to provide further clarification of the original ASU. In addition, the Company is also monitoring the activity of the Power and Utilities Task Force. The Task Force was formed by the American Institute of Certified Public Accountants ("AICPA") in an effort to provide industry-specific guidance. Implementation issues identified by the Task Force include accounting for contributions in aid of construction and assessing collectability of customer accounts when regulated mechanisms exist to allow recovery of uncollected accounts from ratepayers. As of September 30, 2017, the Company continues identifying sources of revenue and evaluating the effect that the revenue guidance will have on financial results and disclosures. Though the evaluation is ongoing, based on the review of customer contracts to date, the Company is not anticipating a material impact to its financial position, results of operations or cash flows upon adoption; however, the Company does anticipate the potential for significant new disclosures as a result of the guidance. Because of ongoing internal analysis and the continued activities of the FASB and other related implementation efforts regarding the rate-regulated natural gas industry, early adoption is not expected. The Company will consider all current and future guidance, including the conclusions of the Task Force, before determining how best to implement the new revenue recognition standard. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities . The ASU enhances the reporting model for financial instruments to provide users of the financial statements with more useful information through several provisions, including the following: (1) requires equity investments, excluding investments accounted for under the equity method, be measured at fair value with changes in fair value recognized in net income, (2) simplifies the impairment assessment of equity investments without readily determinable fair values, (3) eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet, (4) requires entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, and (5) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. The new guidance is effective for the Company for the annual reporting period ending September 30, 2019 and interim periods within that annual period. Management has not completed its evaluation of the new guidance. However, the Company does not currently expect the new guidance to have a material effect on its financial position, results of operations or cash flows. In February 2016, the FASB issued ASU 2016-02, Leases. The ASU leaves the accounting for leases mostly unchanged for lessors, with the exception of targeted improvements for consistency; however, the new guidance requires lessees to recognize assets and liabilities for leases with terms of more than 12 months. The ASU also revises the definition of a lease as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. Consistent with current GAAP, the presentation and cash flows arising from a lease by a lessee will primarily depend on its classification as a finance or operating lease. In contrast, the new ASU requires both types of leases to be recognized on the balance sheet. In addition, the new guidance includes quantitative and qualitative disclosure requirements to aid financial statement users in better understanding the amount, timing and uncertainty of cash flows arising from leases. The new guidance is effective for the Company for the annual reporting period ending September 30, 2020 and interim periods within that annual period. Early adoption is permitted. Management has not completed its evaluation of the new guidance. However, the Company has completed its inventory of leases and does not currently expect the new guidance to have a material effect on its financial position, results of operations or cash flows. In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits . The primary objective of this guidance is to improve the financial statement presentation of net periodic pension and postretirement benefit costs; however, it also changes which cost components are eligible for capitalization. The amendments in the ASU require that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and, if a subtotal for income from operations is presented, outside of income from operations. In addition, the ASU allows only the service cost component of periodic benefit cost to be eligible for capitalization when applicable. This change to capitalization eligibility differs from the treatment currently applied by the Company and from allowed regulatory accounting. The new guidance is effective for the Company for the annual reporting period ending September 30, 2019 and interim periods within that annual period. Early adoption is permitted. Management is in the process of evaluating the new guidance from this ASU. The regulatory body in the Company's service jurisdiction requires the capitalization of all cost components included in net benefit costs. As a result, the Company may have to establish regulatory assets for those costs now excluded from capitalization under this ASU. The Company has begun discussions with its regulatory body, the State Corporation Commission of Virginia, regarding the expected treatment of those costs. Although the ultimate disposition of these other components of net periodic benefit costs has not been determined, management expects the new guidance may have a material effect on the Company's consolidated financial statements when adopted. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting For Hedging Activities . The ASU is meant to simplify recognition and presentation guidance in an effort to improve financial reporting of cash flow and fair value hedging relationships to better portray the economic results of an entity's risk management activities. This is achieved through changes to both the designation and measurement guidance for qualifying hedging relationships, as well as changes to the presentation of hedge results. The new guidance is effective for the Company for the annual reporting period ending September 30, 2020 and interim periods within that annual period. Early adoption is permitted. Management has not completed its evaluation of the new guidance; however, it does not currently expect the new guidance to have a material effect on its financial position, results of operations or cash flows. Other accounting standards that have been issued or proposed by the FASB or other standard–setting bodies are not currently applicable to the Company or are not expected to have a significant impact on the Company’s financial position, results of operations and cash flows.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Regulatory Assets	Regulatory assets and liabilities included in the Company’s consolidated balance sheets as of September 30, 2017 and 2016 are as follows: September 30 2017 2016 Regulatory Assets: Current Assets: Accounts receivable: Accrued WNA revenues $ 248,840 $ 148,663 Other: Accrued pension and postretirement medical 658,786 835,704 Utility Property: In service: Other 11,945 11,945 Other Assets: Regulatory assets: Premium on early retirement of debt 1,941,182 2,055,369 Accrued pension and postretirement medical 8,643,524 11,460,738 Other 1,211,554 816,344 Total regulatory assets $ 12,715,831 $ 15,328,763 Regulatory Liabilities: Current Liabilities: Over-recovery of gas costs $ 1,438,074 $ 909,687 Accrued expenses: Over-recovery of SAVE Plan revenues 215,514 238,694 Deferred Credits and Other Liabilities: Asset retirement obligations 6,069,993 5,682,556 Regulatory cost of retirement obligations 10,055,189 9,348,443 Total regulatory liabilities $ 17,778,770 $ 16,179,380
Schedule of Regulatory Liabilities	Regulatory assets and liabilities included in the Company’s consolidated balance sheets as of September 30, 2017 and 2016 are as follows: September 30 2017 2016 Regulatory Assets: Current Assets: Accounts receivable: Accrued WNA revenues $ 248,840 $ 148,663 Other: Accrued pension and postretirement medical 658,786 835,704 Utility Property: In service: Other 11,945 11,945 Other Assets: Regulatory assets: Premium on early retirement of debt 1,941,182 2,055,369 Accrued pension and postretirement medical 8,643,524 11,460,738 Other 1,211,554 816,344 Total regulatory assets $ 12,715,831 $ 15,328,763 Regulatory Liabilities: Current Liabilities: Over-recovery of gas costs $ 1,438,074 $ 909,687 Accrued expenses: Over-recovery of SAVE Plan revenues 215,514 238,694 Deferred Credits and Other Liabilities: Asset retirement obligations 6,069,993 5,682,556 Regulatory cost of retirement obligations 10,055,189 9,348,443 Total regulatory liabilities $ 17,778,770 $ 16,179,380
Schedule of Utility Plant	Utility plant is composed of the following major classes of assets: Years Ended September 30 2017 2016 Distribution and transmission $ 177,845,619 $ 160,354,300 LNG storage 13,299,288 12,594,294 General and miscellaneous 13,078,807 12,628,692 Total utility plant in service $ 204,223,714 $ 185,577,286
Summary of Asset Retirement Obligation	The following is a summary of the asset retirement obligation: Years Ended September 30 2017 2016 Beginning balance $ 5,682,556 $ 5,295,868 Liabilities incurred 65,556 85,263 Liabilities settled (137,304 ) (176,090 ) Accretion 312,503 310,568 Revisions to estimated cash flows 146,682 166,947 Ending balance $ 6,069,993 $ 5,682,556
Reconciliation of Changes in Allowance for Doubtful Accounts	A reconciliation of changes in the allowance for doubtful accounts is as follows: Years Ended September 30 2017 2016 2015 Beginning balance $ 76,934 $ 52,721 $ 70,747 Provision for doubtful accounts 84,587 14,074 87,908 Recoveries of accounts written off 110,725 137,055 139,282 Accounts written off (172,790 ) (126,916 ) (245,216 ) Ending balance $ 99,456 $ 76,934 $ 52,721
Reconciliation of Basic and Diluted Earnings Per Share	A reconciliation of basic and diluted earnings per share is presented below: Years Ended September 30 2017 2016 2015 Net Income $ 6,232,865 $ 5,806,866 $ 5,094,415 Weighted-average common shares 7,218,686 7,149,906 7,092,315 Effect of dilutive securities: Options to purchase common stock 37,360 9,857 5,199 Diluted average common shares 7,256,046 7,159,763 7,097,514 Earnings Per Share of Common Stock: Basic $ 0.86 $ 0.81 $ 0.72 Diluted $ 0.86 $ 0.81 $ 0.72
Schedule of Interest Rate Derivative	The table below reflects the fair value of the derivative instrument and its corresponding classification in the consolidated balance sheets. September 30 2017 2016 Derivatives designated as hedging instruments: Current assets: Interest rate swap $ 26,777 $ — Other assets: Interest rate swap $ 90,066 $ — Total derivatives designated as hedging instruments $ 116,843 $ —
Summary of Other Comprehensive Income (Loss)	A summary of other comprehensive income is provided below: Before Tax Amount Tax (Expense) or Benefit Net of Tax Amount Year Ended September 30, 2017: Interest rate swap: Unrealized gains $ 116,843 $ (44,354 ) $ 72,489 Net interest rate swap 116,843 (44,354 ) 72,489 Defined benefit plans: Net gain arising during period $ 1,715,505 $ (651,892 ) $ 1,063,613 Amortization of actuarial losses 256,234 (97,369 ) 158,865 Net defined benefit plans 1,971,739 (749,261 ) 1,222,478 Other comprehensive income $ 2,088,582 $ (793,615 ) $ 1,294,967 Year Ended September 30, 2016: Defined benefit plans: Net loss arising during period $ (560,887 ) $ 213,137 $ (347,750 ) Amortization of actuarial losses 221,070 (84,006 ) 137,064 Net defined benefit plans (339,817 ) 129,131 (210,686 ) Other comprehensive loss $ (339,817 ) $ 129,131 $ (210,686 ) Year Ended September 30, 2015: Defined benefit plans: Net loss arising during period (1,910,573 ) 726,017 (1,184,556 ) Amortization of actuarial losses 60,221 (22,884 ) 37,337 Net defined benefit plans (1,850,352 ) 703,133 (1,147,219 ) Other comprehensive loss $ (1,850,352 ) $ 703,133 $ (1,147,219 )
Components of Accumulated Comprehensive Income (Loss)	Composition of Accumulated Other Comprehensive Income (Loss): Interest Rate Swaps Defined Benefit Plans Accumulated Other Comprehensive Income (Loss) Balance September 30, 2014 $ — $ (1,139,326 ) $ (1,139,326 ) Other comprehensive income (loss) — (1,147,219 ) (1,147,219 ) Balance September 30, 2015 — (2,286,545 ) (2,286,545 ) Other comprehensive income (loss) — (210,686 ) (210,686 ) Balance September 30, 2016 — (2,497,231 ) (2,497,231 ) Other comprehensive income (loss) 72,489 1,222,478 1,294,967 Balance September 30, 2017 $ 72,489 $ (1,274,753 ) $ (1,202,264 )

Other Investments (Tables)

Other Investments (Tables)	12 Months Ended
	Sep. 30, 2017
Other Investments [Abstract]
Schedule of Other Investments	The financial statement locations of the investment in the LLC are as follows: September 30 Balance Sheet Location of Other Investments: 2017 2016 Other Assets: Investment in unconsolidated affiliate $ 7,445,106 $ 3,496,404 Current Liabilities: Capital contributions payable $ 1,055,504 $ 287,794 For the Years ended September 30 Income Statement Location of Other Investments: 2017 2016 2015 Equity in earnings of unconsolidated affiliate $ 421,646 $ 152,864 $ —

Line-of-Credit (Tables)

Line-of-Credit (Tables)	12 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Summary of Available Limits Under Line of Credit Agreement	Available limits under this agreement for the remaining term are as follows: As of Available Line-of-Credit September 30, 2017 $ 21,000,000 March 1, 2018 17,000,000 July 22, 2018 22,000,000 September 22, 2018 30,000,000
Summary of Line of Credit	A summary of the line-of-credit follows: September 30 2017 2016 2015 Line-of-credit at year-end $ 21,000,000 $ 24,000,000 $ 24,000,000 Outstanding balance at year-end 17,791,760 14,556,785 9,340,997 Highest month-end balance outstanding 17,791,760 15,246,089 17,366,052 Average daily balance 10,936,114 9,620,914 6,377,040 Average rate of interest during year on outstanding balances 1.92 % 1.40 % 1.17 % Interest rate at year-end 2.23 % 1.53 % 1.20 % Interest rate on unused line-of-credit 0.15 % 0.15 % 0.15 %

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	Long-term debt consists of the following: September 30 2017 2016 Principal Unamortized Debt Issuance Costs Principal Unamortized Debt Issuance Costs Roanoke Gas Company: Unsecured senior notes payable, at 4.26%, due on September 18, 2034 $ 30,500,000 $ 164,119 $ 30,500,000 $ 173,773 Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 7,000,000 13,618 — — Pending unsecured note — 48,160 — — RGC Midstream, LLC: Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020 $ 6,312,200 $ 66,052 $ 3,396,200 $ 86,376 Total notes payable $ 43,812,200 $ 291,949 $ 33,896,200 $ 260,149 Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019 17,791,760 — — — Total long-term debt $ 61,603,960 $ 291,949 $ 33,896,200 $ 260,149
Summary of Aggregate Annual Maturities of Long-Term Debt	The aggregate annual maturities of long-term debt for the next five years ending after September 30, 2017 are as follows: Year Ending September 30 Maturities 2018 $ — 2019 17,791,760 2020 — 2021 6,312,200 2022 7,000,000 Thereafter 30,500,000 Total $ 61,603,960

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Details of Income Tax Expense	The details of income tax expense are as follows: Years Ended September 30 2017 2016 2015 Current income taxes: Federal $ 72,368 $ (1,216,745 ) $ 379,180 State 407,643 415,975 374,541 Total current income taxes 480,011 (800,770 ) 753,721 Deferred income taxes: Federal 3,129,925 4,302,906 2,289,729 State 195,454 164,048 127,112 Total deferred income taxes 3,325,379 4,466,954 2,416,841 Total income tax expense $ 3,805,390 $ 3,666,184 $ 3,170,562
Reconciliation of Income Tax Expense Based on Federal Statutory Rate	Income tax expense for the years ended September 30, 2017 , 2016 and 2015 differed from amounts computed by applying the U.S. Federal income tax rate of 34% to earnings before income taxes due to the following: Years Ended September 30 2017 2016 2015 Income before income taxes $ 10,038,255 $ 9,473,050 $ 8,264,977 Income tax expense computed at the federal statutory rate $ 3,413,007 $ 3,220,837 $ 2,810,092 State income taxes, net of federal income tax benefit 398,044 382,815 331,091 Other, net (5,661 ) 62,532 29,379 Total income tax expense $ 3,805,390 $ 3,666,184 $ 3,170,562
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to the deferred tax assets and deferred tax liabilities are as follows: September 30 2017 2016 Deferred tax assets: Allowance for uncollectibles $ 37,752 $ 29,203 Accrued pension and postretirement medical benefits 1,747,429 2,532,672 Accrued vacation 239,414 262,273 Over-recovery of gas costs 545,894 345,318 Costs of gas held in storage 1,009,206 1,077,849 Deferred compensation 824,281 770,868 Other 348,833 340,121 Total gross deferred tax assets 4,752,809 5,358,304 Deferred tax liabilities: Utility plant 27,630,486 24,264,165 MVP investment 154,817 40,776 Other 44,354 11,217 Total gross deferred tax liabilities 27,829,657 24,316,158 Net deferred tax liability $ 23,076,848 $ 18,957,854

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Schedule of Changes in Benefit Obligations and Fair Value of Plan Assets, Funded Status of the Plan, and Amount Recognized in the Financial Statements	The following tables set forth the benefit obligation, fair value of plan assets, the funded status of the benefit plans, amounts recognized in the Company’s financial statements and the assumptions used. Pension Plan Postretirement Plan 2017 2016 2017 2016 Accumulated benefit obligation $ 25,481,993 $ 25,090,968 $ 17,666,812 $ 18,504,710 Change in benefit obligation: Benefit obligation at beginning of year $ 29,494,950 $ 27,167,621 $ 18,504,710 $ 15,355,668 Service cost 706,677 694,375 183,267 148,018 Interest cost 995,598 1,132,776 626,822 624,579 Actuarial (gain) loss (824,361 ) 2,440,957 (1,199,722 ) 2,812,516 Benefit payments, net of retiree contributions (715,517 ) (1,940,779 ) (448,265 ) (436,071 ) Benefit obligation at end of year $ 29,657,347 $ 29,494,950 $ 17,666,812 $ 18,504,710 Change in fair value of plan assets: Fair value of plan assets at beginning of year $ 23,113,057 $ 21,394,399 $ 11,122,783 $ 10,443,629 Actual return on plan assets, net of taxes 3,021,131 2,159,437 1,016,644 615,225 Employer contributions 1,000,000 1,500,000 1,000,000 500,000 Benefit payments, net of retiree contributions (715,517 ) (1,940,779 ) (448,265 ) (436,071 ) Fair value of plan assets at end of year $ 26,418,671 $ 23,113,057 $ 12,691,162 $ 11,122,783 Funded status $ (3,238,676 ) $ (6,381,893 ) $ (4,975,650 ) $ (7,381,927 ) Amounts recognized in the balance sheets consist of: Noncurrent liabilities $ (3,238,676 ) $ (6,381,893 ) $ (4,975,650 ) $ (7,381,927 ) Amounts recognized in accumulated other comprehensive loss: Net actuarial loss, net of tax $ 572,740 $ 1,583,345 $ 702,013 $ 913,886 Total amounts included in other comprehensive loss, net of tax $ 572,740 $ 1,583,345 $ 702,013 $ 913,886 Amounts deferred to a regulatory asset: Net actuarial loss $ 5,471,547 $ 6,732,800 $ 3,830,763 $ 5,563,642 Amounts recognized as regulatory assets $ 5,471,547 $ 6,732,800 $ 3,830,763 $ 5,563,642
Schedule of Actuarial Assumptions Used	The following table details the actuarial assumptions used in determining the projected benefit obligations and net benefit cost of the pension and the accumulated benefit obligations and net benefit cost of the postretirement plan for 2017 , 2016 and 2015 . Pension Plan Postretirement Plan 2017 2016 2015 2017 2016 2015 Assumptions used to determine benefit obligations: Discount rate 3.72 % 3.42 % 4.22 % 3.69 % 3.33 % 4.15 % Expected rate of compensation increase 4.00 % 4.00 % 4.00 % N/A N/A N/A Assumptions used to determine benefit costs: Discount rate 3.42 % 4.22 % 4.22 % 3.33 % 4.15 % 4.10 % Expected long-term rate of return on plan assets 7.00 % 7.00 % 7.00 % 4.84 % 4.89 % 4.90 % Expected rate of compensation increase 4.00 % 4.00 % 4.00 % N/A N/A N/A
Schedule of Components of Net Periodic Benefit Cost	Components of net periodic benefit cost are as follows: Pension Plan Postretirement Plan 2017 2016 2015 2017 2016 2015 Service cost $ 706,677 $ 694,375 $ 654,782 $ 183,267 $ 148,018 $ 167,580 Interest cost 995,598 1,132,776 1,025,908 626,822 624,579 600,096 Expected return on plan assets (1,616,412 ) (1,492,241 ) (1,440,846 ) (571,513 ) (507,858 ) (516,656 ) Recognized loss 662,180 501,678 257,378 429,758 250,173 197,058 Net periodic benefit cost $ 748,043 $ 836,588 $ 497,222 $ 668,334 $ 514,912 $ 448,078
Summary of Assumed Health Care Cost Trend Rates Used	The assumed health care cost trend rates used in measuring the accumulated benefit obligation for the postretirement medical plan as of September 30, 2017 , 2016 and 2015 are presented below: Pre 65 Post 65 2017 2016 2015 2017 2016 2015 Health care cost trend rate assumed for next year 7.00 % 7.50 % 8.00 % 5.00 % 5.00 % 5.00 % Rate to which the cost trend is assumed to decline (the ultimate trend rate) 5.00 % 5.00 % 5.00 % 5.00 % 5.00 % 5.00 % Year that the rate reaches the ultimate trend rate 2021 2021 2021 2017 2016 2015
Effect of a 1% Change in Health Care Cost Trend Rate Assumptions	The health care cost trend rate assumptions could have a significant effect on the amounts reported. A change of 1% would have the following effects: 1% Increase 1% Decrease Effect on total service and interest cost components $ 153,000 $ (121,000 ) Effect on accumulated postretirement benefit obligation 2,961,000 (2,385,000 )
Schedule of Target and Actual Asset Allocation	The Company’s target and actual asset allocation in the pension and postretirement benefit plans as of September 30, 2017 and 2016 were: Pension Plan Postretirement Target 2017 2016 Target 2017 2016 Asset category: Equity securities 60 % 63 % 63 % 50 % 51 % 52 % Debt securities 40 % 36 % 36 % 50 % 48 % 47 % Cash — % 1 % 1 % — % 1 % — % Other — % — % — % — % — % 1 %
Summary of Fair Value Classifications of Benefit Plan Assets	The following table contains the fair value classifications of the benefit plan assets: Defined Benefit Pension Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 265,100 $ 265,100 $ — $ — Common and Collective Trust and Pooled Funds: Bonds Liability Driven Investment 9,635,998 — 9,635,998 — Equities Domestic Large Cap Growth 5,068,282 — 5,068,282 — Domestic Large Cap Value 5,046,530 — 5,046,530 — Domestic Small/Mid Cap Core 2,393,221 — 2,393,221 — Foreign Large Cap Value 2,139,733 — 2,139,733 — Mutual Funds: Bonds Equities Foreign Large Cap Growth 399,909 — 399,909 — Foreign Large Cap Value 398,995 — 398,995 — Foreign Large Cap Core 1,070,903 — 1,070,903 — Total $ 26,418,671 $ 265,100 $ 26,153,571 $ — Defined Benefit Pension Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 117,265 $ 117,265 $ — $ — Common and Collective Trust and Pooled Funds: Bonds Domestic Fixed Income 4,497,373 — 4,497,373 — Equities Domestic Large Cap Growth 3,426,041 — 3,426,041 — Domestic Large Cap Value 4,543,385 — 4,543,385 — Domestic Small/Mid Cap Core 2,149,566 — 2,149,566 — Foreign Large Cap Value 1,795,897 — 1,795,897 — Mutual Funds: Bonds Domestic Fixed Income 3,615,209 — 3,615,209 — Foreign Fixed Income 234,622 — 234,622 — Equities Domestic Large Cap Growth 1,043,395 — 1,043,395 — Foreign Large Cap Growth 366,420 — 366,420 — Foreign Large Cap Value 373,480 — 373,480 — Foreign Large Cap Core 950,404 — 950,404 — Total $ 23,113,057 $ 117,265 $ 22,995,792 $ — Postretirement Benefit Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 64,616 $ 64,616 $ — $ — Mutual Funds Bonds Domestic Fixed Income 5,727,258 — 5,727,258 — Foreign Fixed Income 359,460 — 359,460 — Equities Domestic Large Cap Growth 1,998,971 — 1,998,971 — Domestic Large Cap Value 1,998,714 — 1,998,714 — Domestic Small/Mid Cap Growth 209,332 — 209,332 — Domestic Small/Mid Cap Value 209,630 — 209,630 — Domestic Small/Mid Cap Core 455,867 — 455,867 — Foreign Large Cap Growth 39,107 — 39,107 — Foreign Large Cap Value 1,079,766 — 1,079,766 — Foreign Large Cap Core 511,298 — 511,298 — Other 37,143 — 37,143 — Total $ 12,691,162 $ 64,616 $ 12,626,546 $ — Postretirement Benefit Plan Fair Value Level 1 Level 2 Level 3 Asset Class: Cash $ 43,455 $ 43,455 $ — $ — Mutual Funds Bonds Domestic Fixed Income 5,109,834 — 5,109,834 — Foreign Fixed Income 87,821 — 87,821 — Equities Domestic Large Cap Growth 1,824,796 — 1,824,796 — Domestic Large Cap Value 1,770,664 — 1,770,664 — Domestic Small/Mid Cap Growth 195,319 — 195,319 — Domestic Small/Mid Cap Value 198,884 — 198,884 — Domestic Small/Mid Cap Core 427,409 — 427,409 — Foreign Large Cap Value 964,827 — 964,827 — Foreign Large Cap Core 456,100 — 456,100 — Other 43,674 — 43,674 — Total $ 11,122,783 $ 43,455 $ 11,079,328 $ —
Schedule of Expected Future Benefit Payments	The following table reflects expected future benefit payments: Fiscal year ending September 30 Pension Postretirement 2018 $ 817,861 $ 618,241 2019 879,779 644,666 2020 966,930 671,228 2021 1,041,200 710,495 2022 1,139,637 749,674 2023-2027 6,981,849 4,148,403

Common Stock Options (Tables)

Common Stock Options (Tables)	12 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Fair Value of Stock Options	As the Company's stock options are not traded on the open market, the fair value of each grant is estimated on the date of grant using the Black-Scholes option pricing model including the following assumptions: Years Ended September 30, 2017 2016 2015 Expected volatility 26.09% 28.78% 34.34% Expected dividends 3.81% 3.99% 4.11% Expected exercise term (years) 7.00 7.00 7.00 Risk-free interest rate 2.20% 2.10% 1.98%
Schedule of Stock Option Transactions	The information contained in the tables below have been restated to reflect the effect of the stock split: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Terms (years) Aggregate Intrinsic Value 1 Options outstanding, September 30, 2014 57,000 $ 12.65 8.8 $ 34,840 Options granted 25,500 14.40 Options exercised (3,900 ) 12.66 Options expired — — Options forfeited — — Options outstanding, September 30, 2015 78,600 13.22 8.3 43,086 Options granted 24,000 14.15 Options exercised (3,300 ) 12.65 Options expired — — Options forfeited (12,000 ) 13.20 Options outstanding, September 30, 2016 87,300 13.50 7.8 200,211 Options granted 25,500 16.37 Options exercised (11,225 ) 12.67 Options expired — — Options forfeited — — Options outstanding, September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 Vested and exercisable at September 30, 2017 101,575 $ 14.31 7.6 $ 1,448,338 1 Aggregate intrinsic value includes only those options where the exercise price is below the market price. Years Ended September 30, 2017 2016 2015 Weighted-average grant date option fair value $ 2.89 $ 2.69 $ 3.28 Stock option expense 73,780 64,640 83,640 Intrinsic value of options exercised 99,929 8,418 5,624 Proceeds from exercise of stock options 142,241 41,762 49,366

Other Stock Plans (Tables)

Other Stock Plans (Tables)	12 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Director Compensation Activity	The following table reflects the director compensation activity pursuant to the Plan: 2017 2016 2015 Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Shares Weighted-Average Fair Value on Date of Grant Beginning of year balance 107,023 $ 10.11 100,373 $ 9.80 94,267 $ 9.53 Granted 4,870 16.77 6,650 14.79 6,106 13.92 Vested — — — — — — Forfeited — — — — — — End of year balance 111,893 $ 10.56 107,023 $ 10.11 100,373 $ 9.80

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Volumetric and Pipeline and Storage Capacity Obligations	The table below details the volumetric obligations as of September 30, 2017 for the remainder of the contract period. The current asset management contract will expire in March 2018. Year Natural Gas Contracts 2017-2018 369,828 Total 369,828 The table below details the pipeline and storage capacity obligations as of September 30, 2017 for the remainder of the contract period. Year Pipeline and 2017-2018 $ 11,232,436 2018-2019 10,113,115 2019-2020 7,633,155 2020-2021 5,221,751 2021-2022 4,565,743 Thereafter 3,067,053 Total $ 41,833,253

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis	The following table summarizes the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and the fair value measurements by level within the fair value hierarchy as defined in Note 1 as of September 30, 2017 and 2016 , respectively: Fair Value Measurements - September 30, 2017 Fair Value Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ 116,843 $ — $ 116,843 $ — Total $ 116,843 $ — $ 116,843 $ — Liabilities: Natural gas purchases $ 805,159 $ — $ 805,159 $ — Total $ 805,159 $ — $ 805,159 $ — Fair Value Measurements - September 30, 2016 Fair Value Quoted Prices in Significant Other Significant Liabilities: Natural gas purchases $ 1,052,930 $ — $ 1,052,930 $ — Total $ 1,052,930 $ — $ 1,052,930 $ —
Summary of the Fair Value of Financial Assets and Liabilities Not Adjusted to Fair Value	The following table summarizes the fair value of the Company’s financial assets and liabilities that are not adjusted to fair value in the financial statements as of September 30, 2017 and 2016 . Fair Value Measurements - September 30, 2017 Carrying Quoted Prices in Significant Other Significant Liabilities: Long-term debt $ 43,812,200 $ — $ — $ 45,689,238 Total $ 43,812,200 $ — $ — $ 45,689,238 Fair Value Measurements - September 30, 2016 Carrying Quoted Prices in Significant Other Significant Liabilities: Long-term debt $ 33,896,200 $ — $ — $ 36,163,523 Total $ 33,896,200 $ — $ — $ 36,163,523

Quarterly Financial Informati34

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Data	Quarterly financial data for the years ended September 30, 2017 and 2016 is summarized as follows: 2017 First Second Third Fourth Operating revenues $ 18,788,585 $ 21,900,013 $ 11,435,824 $ 10,172,448 Gross margin $ 9,390,905 $ 10,829,730 $ 6,634,402 $ 5,954,120 Operating income $ 3,982,275 $ 5,589,207 $ 1,328,207 $ 766,620 Net income $ 2,232,218 $ 3,225,199 $ 615,562 $ 159,886 Earnings per share of common stock: Basic $ 0.31 $ 0.45 $ 0.09 $ 0.02 Diluted $ 0.31 $ 0.45 $ 0.08 $ 0.02 2016 First Second Third Fourth Operating revenues $ 16,010,056 $ 21,777,773 $ 11,295,197 $ 9,980,265 Gross margin $ 8,738,116 $ 10,649,269 $ 6,312,340 $ 5,865,189 Operating income $ 3,498,052 $ 5,444,314 $ 1,453,350 $ 816,376 Net income $ 1,922,790 $ 3,111,447 $ 627,068 $ 145,561 Earnings per share of common stock: Basic $ 0.27 $ 0.44 $ 0.09 $ 0.02 Diluted $ 0.27 $ 0.44 $ 0.09 $ 0.02

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Sep. 30, 2017USD ($)pipelineinstruments_heldsegmentinstrument_heldcustomer	Sep. 30, 2016USD ($)instrument_held	Sep. 30, 2015	Nov. 01, 2017	Nov. 01, 2016
Summary Of Significant Accounting Policies [Line Items]
Number of customers | customer	59,800
Number of reportable segments | segment	1
Remaining amount of regulatory assets that did not earn a return during the recovery period	$ 12,703,886
Regulatory utility assets provision, review period	5 years
Composite weighted-average depreciation rate	3.29%	3.25%	3.25%
Unbilled revenue	$ 965,683	$ 1,004,061
Deferred charges, amortization period	12 months
Number of pipelines | pipeline	2
Unsecured term note	$ 61,603,960	33,896,200
Non-cash change in investment in unconsolidated affiliate	$ 767,710	$ 287,794
Natural Gas
Summary Of Significant Accounting Policies [Line Items]
Number of derivative instruments	0	0
Interest Rate Swap
Summary Of Significant Accounting Policies [Line Items]
Number of derivative instruments | instrument_held	1
Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life (in years)	5 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life (in years)	76 years
Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 | Roanoke Gas | Unsecured Debt
Summary Of Significant Accounting Policies [Line Items]
Unsecured term note	$ 7,000,000
Fixed rate related to interest rate swap					2.30%
Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 | Roanoke Gas | Unsecured Debt | Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Fixed rate related to interest rate swap				2.30%

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Schedule of Regulatory Assets and Liabilities) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Regulatory Assets [Line Items]
Noncurrent regulatory assets	$ 11,796,260	$ 14,332,451
Total regulatory assets	12,715,831	15,328,763
Regulatory Liabilities [Line Items]
Total regulatory liabilities	17,778,770	16,179,380
Over-recovery of gas costs
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1,438,074	909,687
Over-recovery of SAVE Plan revenues
Regulatory Liabilities [Line Items]
Current regulatory liabilities	215,514	238,694
Asset retirement obligations
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	6,069,993	5,682,556
Regulatory cost of retirement obligations
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	10,055,189	9,348,443
Accrued WNA revenues
Regulatory Assets [Line Items]
Current regulatory assets	248,840	148,663
Accrued pension and postretirement medical
Regulatory Assets [Line Items]
Current regulatory assets	658,786	835,704
Noncurrent regulatory assets	8,643,524	11,460,738
Utility property, in service, other
Regulatory Assets [Line Items]
Noncurrent regulatory assets	11,945	11,945
Premium on early retirement of debt
Regulatory Assets [Line Items]
Noncurrent regulatory assets	1,941,182	2,055,369
Other
Regulatory Assets [Line Items]
Noncurrent regulatory assets	$ 1,211,554	$ 816,344

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Components of Utility Plant) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Distribution and transmission	$ 177,845,619	$ 160,354,300
LNG storage	13,299,288	12,594,294
General and miscellaneous	13,078,807	12,628,692
Total utility plant in service	$ 204,223,714	$ 185,577,286

Summary of Significant Accoun38

Summary of Significant Accounting Policies (Summary of Asset Retirement Obligations) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 5,682,556	$ 5,295,868
Liabilities incurred	65,556	85,263
Liabilities settled	(137,304)	(176,090)
Accretion	312,503	310,568
Revisions to estimated cash flows	146,682	166,947
Ending balance	$ 6,069,993	$ 5,682,556

Summary of Significant Accoun39

Summary of Significant Accounting Policies (Reconciliation of Changes in Allowance for Doubtful Accounts) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	$ 76,934	$ 52,721	$ 70,747
Provision for doubtful accounts	84,587	14,074	87,908
Recoveries of accounts written off	110,725	137,055	139,282
Accounts written off	(172,790)	(126,916)	(245,216)
Ending balance	$ 99,456	$ 76,934	$ 52,721

Summary of Significant Accoun40

Summary of Significant Accounting Policies (Reconciliation of Basic and Diluted Earnings Per Share) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net income	$ 159,886	$ 615,562	$ 3,225,199	$ 2,232,218	$ 145,561	$ 627,068	$ 3,111,447	$ 1,922,790	$ 6,232,865	$ 5,806,866	$ 5,094,415
Weighted-average common shares (in shares)									7,218,686	7,149,906	7,092,315
Effect of dilutive securities:
Options to purchase common stock (in shares)									37,360	9,857	5,199
Diluted average common shares (in shares)									7,256,046	7,159,763	7,097,514
Earnings Per Share of Common Stock:
Basic (in usd per share)	$ 0.02	$ 0.09	$ 0.45	$ 0.31	$ 0.02	$ 0.09	$ 0.44	$ 0.27	$ 0.86	$ 0.81	$ 0.72
Diluted (in usd per share)	$ 0.02	$ 0.08	$ 0.45	$ 0.31	$ 0.02	$ 0.09	$ 0.44	$ 0.27	$ 0.86	$ 0.81	$ 0.72

Summary of Significant Accoun41

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Schedule of Interest Rate Derivative) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest rate swap, current assets	$ 26,777	$ 0
Interest rate swap, other assets	90,066	0
Total derivatives designated as hedging instruments	$ 116,843	$ 0

Summary of Significant Accoun42

Summary of Significant Accounting Policies (Summary of Other Comprehensive Income) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Before Tax Amount
Unrealized gains	$ 116,843
Net interest rate swap	116,843
Net gain (loss) arising during period	1,715,505	$ (560,887)	$ (1,910,573)
Amortization of actuarial losses	256,234	221,070	60,221
Net defined benefit plans	1,971,739	(339,817)	(1,850,352)
Other comprehensive income (loss)	2,088,582	(339,817)	(1,850,352)
Tax (Expense) or Benefit
Unrealized gains	(44,354)
Net interest rate swap	(44,354)
Net gain (loss) arising during period	(651,892)	213,137	726,017
Amortization of actuarial losses	(97,369)	(84,006)	(22,884)
Net defined benefit plans	(749,261)	129,131	703,133
Other comprehensive income (loss)	(793,615)	129,131	703,133
Net of Tax Amount
Unrealized gains	72,489
Net interest rate swap	72,489	0	0
Net gain (loss) arising during period	1,063,613	(347,750)	(1,184,556)
Amortization of actuarial losses	158,865	137,064	37,337
Net defined benefit plans	1,222,478	(210,686)	(1,147,219)
OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	$ 1,294,967	$ (210,686)	$ (1,147,219)

Summary of Significant Accoun43

Summary of Significant Accounting Policies (Components of Accumulated Comprehensive Income (Loss)) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Interest Rate Swaps
Balance at beginning of period	$ 0	$ 0	$ 0
Other comprehensive income (loss)	72,489	0	0
Balance at end of period	72,489	0	0
Defined Benefit Plans
Balance at beginning of period	(2,497,231)	(2,286,545)	(1,139,326)
Other comprehensive income (loss)	1,222,478	(210,686)	(1,147,219)
Balance at end of period	(1,274,753)	(2,497,231)	(2,286,545)
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	(2,497,231)	(2,286,545)	(1,139,326)
Other comprehensive income (loss)	1,294,967	(210,686)	(1,147,219)
Balance at end of period	$ (1,202,264)	$ (2,497,231)	$ (2,286,545)

Stock Split (Details)

Stock Split (Details) - USD ($)	Mar. 01, 2017	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Common stock dividend from stock split (percentage)	50.00%
Stock split ratio	1.5
Common stock, par value (in usd per share)		$ 5	$ 5
Adjustments to additional paid in capital, stock split	$ 10,025,546	$ 0
Adjustments to retained earnings, stock split	$ 2,004,244
Stock issued, shares, stock split	2,405,958

Other Investments (Narrative) (

Other Investments (Narrative) (Details) Bcf in Millions	12 Months Ended
	Sep. 30, 2017USD ($)debt_instrumentBcf	Sep. 30, 2016USD ($)	Dec. 31, 2015
Investment [Line Items]
Investments unconsolidated affiliate	$ 7,445,106	$ 3,496,404
Promissory Notes term	20 years
RGC Midstream, LLC
Investment [Line Items]
Equity interest (as a percent)	1.00%		1.00%
Pipeline capacity (in bcf per day) | Bcf	2
Total project cost	$ 3,500,000,000
Total estimated investment	$ 35,000,000
Number of unsecured Promissory Notes funding the investment | debt_instrument	2
Promissory Notes term	5 years

Other Investments (Schedule of

Other Investments (Schedule of Other Investments) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Other Investments [Abstract]
Investment in unconsolidated affiliate	$ 7,445,106	$ 3,496,404
Capital contributions payable	1,055,504	287,794
Equity in earnings of unconsolidated affiliate	$ 421,646	$ 152,864	$ 0

Line-of-Credit (Narrative) (Det

Line-of-Credit (Narrative) (Details)	6 Months Ended	12 Months Ended
	Mar. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Promissory Notes term		20 years
Interest rate on unused line-of-credit (as a percent)		0.15%	0.15%	0.15%
Debt covenant, maximum ratio of total long-term debt to total capitalization		65.00%
Roanoke Gas | Line of Credit
Debt Instrument [Line Items]
Promissory Notes term	1 year
Roanoke Gas | Line of Credit | Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019
Debt Instrument [Line Items]
Promissory Notes term		2 years
Variable rate basis points (as a percent)		1.00%
Interest rate on unused line-of-credit (as a percent)		0.15%
Minimum interest coverage ratio		1.5
Debt covenant, maximum ratio of total long-term debt to total capitalization		65.00%

Line-of-Credit (Summary of Avai

Line-of-Credit (Summary of Available Limits Under Line of Credit Agreement) (Details)	Sep. 30, 2017USD ($)
September 30, 2017
Short-term Debt [Line Items]
Available Line-of-Credit	$ 21,000,000
March 1, 2018
Short-term Debt [Line Items]
Available Line-of-Credit	17,000,000
July 22, 2018
Short-term Debt [Line Items]
Available Line-of-Credit	22,000,000
September 22, 2018
Short-term Debt [Line Items]
Available Line-of-Credit	$ 30,000,000

Line-of-Credit (Summary of Line

Line-of-Credit (Summary of Line-of-Credit) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Debt Disclosure [Abstract]
Line-of-credit at year-end	$ 21,000,000	$ 24,000,000	$ 24,000,000
Outstanding balance at year-end	17,791,760	14,556,785	9,340,997
Highest month-end balance outstanding	17,791,760	15,246,089	17,366,052
Average daily balance	$ 10,936,114	$ 9,620,914	$ 6,377,040
Average rate of interest during year on outstanding balances (as a percent)	1.92%	1.40%	1.17%
Interest rate at year-end (as a percent)	2.23%	1.53%	1.20%
Interest rate on unused line-of-credit (as a percent)	0.15%	0.15%	0.15%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	Oct. 02, 2017USD ($)	Nov. 01, 2016USD ($)	Dec. 31, 2015USD ($)instruments_held	Mar. 31, 2017	Sep. 30, 2017USD ($)debt_instrument	Nov. 01, 2017	Sep. 30, 2016USD ($)
Debt Instrument [Line Items]
Promissory Notes term					20 years
Unamortized loss on early retirement of debt deferred as regulatory asset					$ 1,941,182		$ 2,055,369
Unamortized loss on early retirement of debt, amortization period					20 years
Debt covenant, maximum ratio of total long-term debt to total capitalization					65.00%
Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021
Debt Instrument [Line Items]
Promissory Notes term		5 years
Debt instrument, face amount		$ 7,000,000
Fixed rate related to interest rate swap		2.30%
Debt covenant, maximum ratio of priority indebtedness to total assets					15.00%
Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 | Subsequent Event
Debt Instrument [Line Items]
Fixed rate related to interest rate swap						2.30%
Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 | 30-day LIBOR
Debt Instrument [Line Items]
Variable rate basis points (as a percent)		0.90%			0.90%
Roanoke Gas | Unsecured Debt | Unsecured term notes payable, at 3.58%, due October 2, 2027 | Subsequent Event
Debt Instrument [Line Items]
Promissory Notes term	10 years
Debt instrument, face amount	$ 8,000,000
Stated percentage rate	3.58%
Roanoke Gas | Unsecured Senior Notes | Unsecured senior notes payable, at 4.26%, due on September 18, 2034
Debt Instrument [Line Items]
Debt covenant, maximum ratio of priority indebtedness to total assets					15.00%
Stated percentage rate					4.26%
Roanoke Gas | Line of Credit
Debt Instrument [Line Items]
Promissory Notes term				1 year
Roanoke Gas | Line of Credit | Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019
Debt Instrument [Line Items]
Promissory Notes term					2 years
Variable rate basis points (as a percent)					1.00%
Debt covenant, maximum ratio of total long-term debt to total capitalization					65.00%
Roanoke Gas | Line of Credit | Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019 | 30-day LIBOR
Debt Instrument [Line Items]
Variable rate basis points (as a percent)					1.00%
RGC Midstream, LLC
Debt Instrument [Line Items]
Promissory Notes term					5 years
Number of unsecured Promissory Notes funding the investment | debt_instrument					2
Equity interest (as a percent)			1.00%		1.00%
RGC Midstream, LLC | Unsecured Debt | Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020
Debt Instrument [Line Items]
Promissory Notes term			5 years
Debt instrument, face amount			$ 25,000,000
Number of unsecured Promissory Notes funding the investment | instruments_held			2
Maximum amount borrowed before company equity investment			$ 17,500,000
Equity investment required by credit agreement			$ 5,000,000
Debt covenant, maximum ratio of priority indebtedness to total assets					15.00%
RGC Midstream, LLC | Unsecured Debt | Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020 | 30-day LIBOR
Debt Instrument [Line Items]
Variable rate basis points (as a percent)			1.60%		1.60%

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($)	Nov. 01, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016
Principal
Notes payable			$ 43,812,200	$ 33,896,200
Line-of-credit			17,791,760	0
Total			61,603,960	33,896,200
Unamortized Debt Issuance Costs			291,949	260,149
Notes Payable
Principal
Notes payable			43,812,200	33,896,200
Unamortized Debt Issuance Costs			291,949	260,149
Roanoke Gas | Unsecured Senior Notes | Unsecured senior notes payable, at 4.26%, due on September 18, 2034
Principal
Notes payable			30,500,000	30,500,000
Unamortized Debt Issuance Costs			$ 164,119	173,773
Stated percentage rate			4.26%
Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021
Principal
Notes payable			$ 7,000,000	0
Total			7,000,000
Unamortized Debt Issuance Costs			$ 13,618	0
Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 30-day LIBOR plus 0.90%, November 1, 2021 | 30-day LIBOR
Principal
Variable rate basis points (as a percent)	0.90%		0.90%
Roanoke Gas | Unsecured Debt | Pending unsecured note
Principal
Notes payable			$ 0	0
Unamortized Debt Issuance Costs			48,160	0
Roanoke Gas | Line of Credit | Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019
Principal
Line-of-credit			17,791,760	0
Unamortized Debt Issuance Costs			$ 0	0
Variable rate basis points (as a percent)			1.00%
Roanoke Gas | Line of Credit | Line-of-credit, at 30-day LIBOR plus 1.00%, due March 31, 2019 | 30-day LIBOR
Principal
Variable rate basis points (as a percent)			1.00%
RGC Midstream, LLC | Unsecured Debt | Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020
Principal
Notes payable			$ 6,312,200	3,396,200
Unamortized Debt Issuance Costs			$ 66,052	$ 86,376
RGC Midstream, LLC | Unsecured Debt | Unsecured term notes payable, at 30-day LIBOR plus 1.60% due December 29, 2020 | 30-day LIBOR
Principal
Variable rate basis points (as a percent)		1.60%	1.60%

Long-Term Debt (Summary of Aggr

Long-Term Debt (Summary of Aggregate Maturities of Long-Term Debt) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Maturities
2,018	$ 0
2,019	17,791,760
2,020	0
2,021	6,312,200
2,022	7,000,000
Thereafter	30,500,000
Total	$ 61,603,960	$ 33,896,200

Income Taxes (Details of Income

Income Taxes (Details of Income Tax Expense) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Current income taxes:
Federal	$ 72,368	$ (1,216,745)	$ 379,180
State	407,643	415,975	374,541
Total current income taxes	480,011	(800,770)	753,721
Deferred income taxes:
Federal	3,129,925	4,302,906	2,289,729
State	195,454	164,048	127,112
Total deferred income taxes	3,325,379	4,466,954	2,416,841
Total income tax expense	$ 3,805,390	$ 3,666,184	$ 3,170,562

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Federal income tax rate	34.00%	34.00%	34.00%
Prior year deferred taxes reflected in the current year tax provision		$ 1,283,925	$ 1,442,211

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Income Tax Expense Based on Federal Statutory Rate) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income before income taxes	$ 10,038,255	$ 9,473,050	$ 8,264,977
Income tax expense computed at the federal statutory rate	3,413,007	3,220,837	2,810,092
State income taxes, net of federal income tax benefit	398,044	382,815	331,091
Other, net	(5,661)	62,532	29,379
Total income tax expense	$ 3,805,390	$ 3,666,184	$ 3,170,562

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Deferred tax assets:
Allowance for uncollectibles	$ 37,752	$ 29,203
Accrued pension and postretirement medical benefits	1,747,429	2,532,672
Accrued vacation	239,414	262,273
Over-recovery of gas costs	545,894	345,318
Costs of gas held in storage	1,009,206	1,077,849
Deferred compensation	824,281	770,868
Other	348,833	340,121
Total gross deferred tax assets	4,752,809	5,358,304
Deferred tax liabilities:
Utility plant	27,630,486	24,264,165
MVP investment	154,817	40,776
Other	44,354	11,217
Total gross deferred tax liabilities	27,829,657	24,316,158
Net deferred tax liability	$ 23,076,848	$ 18,957,854

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details)	1 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expected amount of accumulated other comprehensive loss recognized in net periodic benefit costs		$ 24,000
Expected amount of deferred regulatory assets to be recognized in net periodic benefit costs		659,000
Company's matching contribution		$ 361,702	$ 353,793	$ 338,896
After April 2010 | First Portion Match
Defined Benefit Plan Disclosure [Line Items]
Employers percentage match of employees match percentage		100.00%
Percentage of employee's gross pay that is matched by the employer		4.00%
After April 2010 | Second Portion Match
Defined Benefit Plan Disclosure [Line Items]
Employers percentage match of employees match percentage		50.00%
Percentage of employee's gross pay that is matched by the employer		2.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employee contribution percent		1.00%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employee contribution percent		50.00%
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Years until benefits are fully vested		5 years
Number of individuals that accepted pension lump sum pay out			40
Number of individuals eligible for pension lump sum pay out			63
Pension lump sum pay out	$ 1,241,529	$ 715,517	$ 1,940,779
Decrease in projected pension plan obligation after lump sum pay out	$ (1,500,000)
Expected employer contributions in next fiscal year		$ 1,600,000
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Minimum service requirement for postretirement benefit vesting		10 years
Retirement age requirement, postretirement plan		55 years
Pension lump sum pay out		$ 448,265	$ 436,071
Expected employer contributions in next fiscal year		$ 600,000

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule of Changes in Benefit Obligations and Fair Value of Plan Assets, Funded Status of the Plan, and Amount Recognized in the Financial Statements) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Change in fair value of plan assets:
Noncurrent liabilities	$ (13,763,820)	$ (8,214,326)	$ (13,763,820)
Total amounts included in other comprehensive loss, net of tax	2,497,231	1,274,753	2,497,231	$ 2,286,545	$ 1,139,326
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	25,090,968	25,481,993	25,090,968
Change in benefit obligation:
Benefit obligation at beginning of year		29,494,950	27,167,621
Service cost		706,677	694,375	654,782
Interest cost		995,598	1,132,776	1,025,908
Actuarial (gain) loss		(824,361)	2,440,957
Benefit payments, net of retiree contributions	(1,241,529)	(715,517)	(1,940,779)
Benefit obligation at end of year	29,494,950	29,657,347	29,494,950	27,167,621
Change in fair value of plan assets:
Fair value of plan assets at beginning of year		23,113,057	21,394,399
Actual return on plan assets, net of taxes		3,021,131	2,159,437
Employer contributions		1,000,000	1,500,000
Benefit payments, net of retiree contributions		(715,517)	(1,940,779)
Fair value of plan assets at end of year	23,113,057	26,418,671	23,113,057	21,394,399
Funded status	(6,381,893)	(3,238,676)	(6,381,893)
Noncurrent liabilities	(6,381,893)	(3,238,676)	(6,381,893)
Net actuarial loss, net of tax	1,583,345	572,740	1,583,345
Total amounts included in other comprehensive loss, net of tax	1,583,345	572,740	1,583,345
Net actuarial loss	6,732,800	5,471,547	6,732,800
Amounts recognized as regulatory assets	6,732,800	5,471,547	6,732,800
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	18,504,710	17,666,812	18,504,710
Change in benefit obligation:
Benefit obligation at beginning of year		18,504,710	15,355,668
Service cost		183,267	148,018	167,580
Interest cost		626,822	624,579	600,096
Actuarial (gain) loss		(1,199,722)	2,812,516
Benefit payments, net of retiree contributions		(448,265)	(436,071)
Benefit obligation at end of year	18,504,710	17,666,812	18,504,710	15,355,668
Change in fair value of plan assets:
Fair value of plan assets at beginning of year		11,122,783	10,443,629
Actual return on plan assets, net of taxes		1,016,644	615,225
Employer contributions		1,000,000	500,000
Benefit payments, net of retiree contributions		(448,265)	(436,071)
Fair value of plan assets at end of year	11,122,783	12,691,162	11,122,783	$ 10,443,629
Funded status	(7,381,927)	(4,975,650)	(7,381,927)
Noncurrent liabilities	(7,381,927)	(4,975,650)	(7,381,927)
Net actuarial loss, net of tax	913,886	702,013	913,886
Total amounts included in other comprehensive loss, net of tax	913,886	702,013	913,886
Net actuarial loss	5,563,642	3,830,763	5,563,642
Amounts recognized as regulatory assets	$ 5,563,642	$ 3,830,763	$ 5,563,642

Employee Benefit Plans (Sched59

Employee Benefit Plans (Schedule of Actuarial Assumptions Used) (Details)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Pension Plan
Assumptions used to determine benefit obligations:
Discount rate	3.72%	3.42%	4.22%
Expected rate of compensation increase	4.00%	4.00%	4.00%
Assumptions used to determine benefit costs:
Discount rate	3.42%	4.22%	4.22%
Expected long-term rate of return on plan assets	7.00%	7.00%	7.00%
Expected rate of compensation increase	4.00%	4.00%	4.00%
Postretirement Plan
Assumptions used to determine benefit obligations:
Discount rate	3.69%	3.33%	4.15%
Assumptions used to determine benefit costs:
Discount rate	3.33%	4.15%	4.10%
Expected long-term rate of return on plan assets	4.84%	4.89%	4.90%

Employee Benefit Plans (Sched60

Employee Benefit Plans (Schedule of Components of Net Periodic Cost) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 706,677	$ 694,375	$ 654,782
Interest cost	995,598	1,132,776	1,025,908
Expected return on plan assets	(1,616,412)	(1,492,241)	(1,440,846)
Recognized loss	662,180	501,678	257,378
Net periodic benefit cost	748,043	836,588	497,222
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	183,267	148,018	167,580
Interest cost	626,822	624,579	600,096
Expected return on plan assets	(571,513)	(507,858)	(516,656)
Recognized loss	429,758	250,173	197,058
Net periodic benefit cost	$ 668,334	$ 514,912	$ 448,078

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of Assumed Health Care Cost Trend Rates Used) (Details)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Pre 65
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	7.00%	7.50%	8.00%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,021	2,021	2,021
Post 65
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	5.00%	5.00%	5.00%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,017	2,016	2,015

Employee Benefit Plans (Effect

Employee Benefit Plans (Effect of a 1% Change in Health Care Cost Trend Rate Assumptions) (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2017USD ($)
1% Increase
Effect on total service and interest cost components	$ 153
Effect on accumulated postretirement benefit obligation	2,961
1% Decrease
Effect on total service and interest cost components	(121)
Effect on accumulated postretirement benefit obligation	$ (2,385)

Employee Benefit Plans (Sched63

Employee Benefit Plans (Schedule of Target and Actual Asset Allocation) (Details)	Sep. 30, 2017	Sep. 30, 2016
Pension Plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target	60.00%
Actual	63.00%	63.00%
Pension Plan | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target	40.00%
Actual	36.00%	36.00%
Pension Plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Actual	1.00%	1.00%
Pension Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Actual	0.00%	0.00%
Postretirement Plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target	50.00%
Actual	51.00%	52.00%
Postretirement Plan | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target	50.00%
Actual	48.00%	47.00%
Postretirement Plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Actual	1.00%	0.00%
Postretirement Plan | Other
Defined Benefit Plan Disclosure [Line Items]
Target	0.00%
Actual	0.00%	1.00%

Employee Benefit Plans (Summa64

Employee Benefit Plans (Summary of Fair Value Classifications of Benefit Plan Assets ) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	$ 26,418,671	$ 23,113,057	$ 21,394,399
Pension Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	265,100	117,265
Pension Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	26,153,571	22,995,792
Pension Plan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	265,100	117,265
Pension Plan | Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	265,100	117,265
Pension Plan | Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Cash | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Liability Driven Investment
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	9,635,998
Pension Plan | Common and Collective Trust and Pooled Funds | Liability Driven Investment | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0
Pension Plan | Common and Collective Trust and Pooled Funds | Liability Driven Investment | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	9,635,998
Pension Plan | Common and Collective Trust and Pooled Funds | Liability Driven Investment | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		4,497,373
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		4,497,373
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,068,282	3,426,041
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,068,282	3,426,041
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,046,530	4,543,385
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,046,530	4,543,385
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Large Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Small/Mid Cap Core
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	2,393,221	2,149,566
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Small/Mid Cap Core | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Small/Mid Cap Core | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	2,393,221	2,149,566
Pension Plan | Common and Collective Trust and Pooled Funds | Domestic Small/Mid Cap Core | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Foreign Large Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	2,139,733	1,795,897
Pension Plan | Common and Collective Trust and Pooled Funds | Foreign Large Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Common and Collective Trust and Pooled Funds | Foreign Large Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	2,139,733	1,795,897
Pension Plan | Common and Collective Trust and Pooled Funds | Foreign Large Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Domestic Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		3,615,209
Pension Plan | Mutual Funds | Domestic Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Domestic Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		3,615,209
Pension Plan | Mutual Funds | Domestic Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Foreign Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		234,622
Pension Plan | Mutual Funds | Foreign Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Foreign Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		234,622
Pension Plan | Mutual Funds | Foreign Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Domestic Large Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		1,043,395
Pension Plan | Mutual Funds | Domestic Large Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Domestic Large Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		1,043,395
Pension Plan | Mutual Funds | Domestic Large Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets		0
Pension Plan | Mutual Funds | Foreign Large Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	399,909	366,420
Pension Plan | Mutual Funds | Foreign Large Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Foreign Large Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	399,909	366,420
Pension Plan | Mutual Funds | Foreign Large Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Foreign Large Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	398,995	373,480
Pension Plan | Mutual Funds | Foreign Large Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Foreign Large Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	398,995	373,480
Pension Plan | Mutual Funds | Foreign Large Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Foreign Large Cap Core
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,070,903	950,404
Pension Plan | Mutual Funds | Foreign Large Cap Core | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Pension Plan | Mutual Funds | Foreign Large Cap Core | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,070,903	950,404
Pension Plan | Mutual Funds | Foreign Large Cap Core | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	12,691,162	11,122,783	$ 10,443,629
Postretirement Plan | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	64,616	43,455
Postretirement Plan | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	12,626,546	11,079,328
Postretirement Plan | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	64,616	43,455
Postretirement Plan | Cash | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	64,616	43,455
Postretirement Plan | Cash | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Cash | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,727,258	5,109,834
Postretirement Plan | Mutual Funds | Domestic Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	5,727,258	5,109,834
Postretirement Plan | Mutual Funds | Domestic Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	359,460	87,821
Postretirement Plan | Mutual Funds | Foreign Fixed Income | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Fixed Income | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	359,460	87,821
Postretirement Plan | Mutual Funds | Foreign Fixed Income | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Large Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,998,971	1,824,796
Postretirement Plan | Mutual Funds | Domestic Large Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Large Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,998,971	1,824,796
Postretirement Plan | Mutual Funds | Domestic Large Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Large Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,998,714	1,770,664
Postretirement Plan | Mutual Funds | Domestic Large Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Large Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,998,714	1,770,664
Postretirement Plan | Mutual Funds | Domestic Large Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	209,332	195,319
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	209,332	195,319
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	209,630	198,884
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	209,630	198,884
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Core
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	455,867	427,409
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Core | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Core | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	455,867	427,409
Postretirement Plan | Mutual Funds | Domestic Small/Mid Cap Core | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	39,107
Postretirement Plan | Mutual Funds | Foreign Large Cap Growth | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Growth | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	39,107
Postretirement Plan | Mutual Funds | Foreign Large Cap Growth | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,079,766	964,827
Postretirement Plan | Mutual Funds | Foreign Large Cap Value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	1,079,766	964,827
Postretirement Plan | Mutual Funds | Foreign Large Cap Value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Core
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	511,298	456,100
Postretirement Plan | Mutual Funds | Foreign Large Cap Core | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Foreign Large Cap Core | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	511,298	456,100
Postretirement Plan | Mutual Funds | Foreign Large Cap Core | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	37,143	43,674
Postretirement Plan | Mutual Funds | Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	0	0
Postretirement Plan | Mutual Funds | Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	37,143	43,674
Postretirement Plan | Mutual Funds | Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of benefit plan assets	$ 0	$ 0

Employee Benefit Plans (Sched65

Employee Benefit Plans (Schedule of Expected Future Benefit Payments) (Details)	Sep. 30, 2017USD ($)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
2,018	$ 817,861
2,019	879,779
2,020	966,930
2,021	1,041,200
2,022	1,139,637
2023-2027	6,981,849
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
2,018	618,241
2,019	644,666
2,020	671,228
2,021	710,495
2,022	749,674
2023-2027	$ 4,148,403

Common Stock Options (Narrative

Common Stock Options (Narrative) (Details) - shares	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of shares available for future grant	36,000
Award vesting period	6 months
Award expiration period	10 years
Expected exercise term (years)	7 years	7 years	7 years

Common Stock Options (Fair Valu

Common Stock Options (Fair Value Assumptions) (Details)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected volatility (as a percent)	26.09%	28.78%	34.34%
Expected dividends (as a percent)	3.81%	3.99%	4.11%
Expected exercise term (years)	7 years	7 years	7 years
Risk-free interest rate	2.20%	2.10%	1.98%

Common Stock Options (Schedule

Common Stock Options (Schedule of Stock Option Activity) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Number of Shares
Options outstanding, beginning balance (in shares)	87,300	78,600	57,000
Options granted (in shares)	25,500	24,000	25,500
Options exercised (in shares)	(11,225)	(3,300)	(3,900)
Options expired (in shares)	0	0	0
Options forfeited (in shares)	0	(12,000)	0
Options outstanding, ending balance (in shares)	101,575	87,300	78,600	57,000
Vested and exercisable at end of period (in shares)	101,575
Weighted- Average Exercise Price
Options outstanding, beginning balance (in usd per share)	$ 13.50	$ 13.22	$ 12.65
Options granted (in usd per share)	16.37	14.15	14.40
Options exercised (in usd per share)	12.67	12.65	12.66
Options expired (in usd per share)	0	0	0
Options forfeited (in usd per share)	0	13.20	0
Options outstanding, ending balance (in usd per share)	14.31	$ 13.50	$ 13.22	$ 12.65
Vested and exercisable at end of period (in usd per share)	$ 14.31
Options, Additional Disclosures
Weighted- Average Remaining Contractual Terms (years)	7 years 7 months	7 years 10 months	8 years 4 months	8 years 9 months
Weighted-Average Remaining Contractual Term, Vested and exercisable at September 30, 2017	7 years 7 months
Aggregate Intrinsic Value	$ 1,448,338	$ 200,211	$ 43,086	$ 34,840
Aggregate Intrinsic Value, Vested and exercisable at end of period	$ 1,448,338
Weighted-average grant date option fair value (in usd per share)	$ 2.89	$ 2.69	$ 3.28
Stock option expense	$ 73,780	$ 64,640	$ 83,640
Intrinsic value of options exercised	99,929	8,418	5,624
Proceeds from exercise of stock options	$ 142,241	$ 41,762	$ 49,366

Other Stock Plans (Narrative) (

Other Stock Plans (Narrative) (Details)	Mar. 01, 2017	Sep. 30, 2016shares	Sep. 30, 2017USD ($)shares	Sep. 30, 2016USD ($)shares	Sep. 30, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance			36,000
Stock split ratio	1.5
Dividend Reinvestment and Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum amount shareholders can partake in the DRIP plan | $			$ 40,000
Number of shares issued under the Dividend Reinvestment and Stock Purchase Plan			36,446	52,146	12,647
Shares of stock available for issuance under the DRIP Plan			448,973
Restricted Stock Plan for Outside Directors | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage of monthly retainer fee paid in shares of common stock			40.00%
Minimum number of shares that must be owned to avoid percentage of monthly retainer fee paid in shares of common stock		10,000
Value of shares issued under the plan | $			$ 99,400	$ 98,334	$ 85,000
Stock vested during the period (in shares)			0	0	0
Stock forfeited during the period (in shares)			0	0	0
Shares available for issuance			85,233
Granted (in shares)			4,870	6,650	6,106
RGC Resources, Inc. Restricted Stock Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance			450,000
Shares available for issuance, pre stock split			300,000
Granted (in shares)			0
Stock Bonus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares issued under the plan | $			$ 30,154	$ 39,819	$ 59,332
Shares available for issuance			4,785
Percentage of officers' annual salary expected to be held in company stock			50.00%
Minimum percentage of performance bonus in stock			50.00%
Shares issued under the plan			1,628	2,813	4,097
Stock Bonus Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of officers' annual salary expected to be held in company stock			50.00%

Other Stock Plans (Director Com

Other Stock Plans (Director Compensation Activity) (Details) - Restricted Stock Plan for Outside Directors - Restricted Stock - $ / shares	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Shares
Beginning of year balance (in shares)	107,023	100,373	94,267
Granted (in shares)	4,870	6,650	6,106
Vested (in shares)	0	0	0
Forfeited (in shares)	0	0	0
End of year balance (in shares)	111,893	107,023	100,373
Weighted-Average Fair Value on Date of Grant
Beginning of year balance (in usd per share)	$ 10.11	$ 9.80	$ 9.53
Granted (in usd per share)	16.77	14.79	13.92
Vested (in usd per share)	0	0	0
Forfeited (in usd per share)	0	0	0
End of year balance (in usd per share)	$ 10.56	$ 10.11	$ 9.80

Commitments and Contingencies71

Commitments and Contingencies (Schedule of Volumetric Obligations) (Details)	Sep. 30, 2017MMBTU
Commitments and Contingencies Disclosure [Abstract]
2017-2018	369,828
Total	369,828

Commitments and Contingencies72

Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Expenditures under asset management agreement	$ 28,496	$ 24,852	$ 33,405

Commitments and Contingencies73

Commitments and Contingencies (Schedule of Pipeline and Storage Capacity Obligations) (Details)	Sep. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2017-2018	$ 11,232,436
2018-2019	10,113,115
2019-2020	7,633,155
2020-2021	5,221,751
2021-2022	4,565,743
Thereafter	3,067,053
Total	$ 41,833,253

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Assets:
Interest rate swaps	$ 116,843	$ 0
Total	116,843
Liabilities:
Natural gas purchases	805,159	1,052,930
Total	805,159	1,052,930
Quoted Prices in Active Markets Level 1
Assets:
Interest rate swaps	0
Total	0
Liabilities:
Natural gas purchases	0	0
Total	0	0
Significant Other Observable Inputs Level 2
Assets:
Interest rate swaps	116,843
Total	116,843
Liabilities:
Natural gas purchases	805,159	1,052,930
Total	805,159	1,052,930
Significant Unobservable Inputs Level 3
Assets:
Interest rate swaps	0
Total	0
Liabilities:
Natural gas purchases	0	0
Total	$ 0	$ 0

Fair Value Measurements (Summar

Fair Value Measurements (Summary of the Fair Value of Financial Assets and Liabilities Not Adjusted to Fair Value) (Details) - USD ($)	Sep. 30, 2017	Sep. 30, 2016
Liabilities:
Long-term debt	$ 43,812,200	$ 33,896,200
Total	43,812,200	33,896,200
Quoted Prices in Active Markets Level 1
Liabilities:
Long-term debt	0	0
Total	0	0
Significant Other Observable Inputs Level 2
Liabilities:
Long-term debt	0	0
Total	0	0
Significant Unobservable Inputs Level 3
Liabilities:
Long-term debt	45,689,238	36,163,523
Total	$ 45,689,238	$ 36,163,523

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details)	12 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Treasury rate, period	20 years
Twenty year treasury rate change	0.64%

Quarterly Financial Informati77

Quarterly Financial Information (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 10,172,448	$ 11,435,824	$ 21,900,013	$ 18,788,585	$ 9,980,265	$ 11,295,197	$ 21,777,773	$ 16,010,056	$ 62,296,870	$ 59,063,291	$ 68,189,607
Gross margin	5,954,120	6,634,402	10,829,730	9,390,905	5,865,189	6,312,340	10,649,269	8,738,116	32,809,157	31,564,914	30,206,433
Operating income	766,620	1,328,207	5,589,207	3,982,275	816,376	1,453,350	5,444,314	3,498,052	11,666,309	11,212,092	10,006,192
Net income	$ 159,886	$ 615,562	$ 3,225,199	$ 2,232,218	$ 145,561	$ 627,068	$ 3,111,447	$ 1,922,790	$ 6,232,865	$ 5,806,866	$ 5,094,415
Earnings per share of common stock:
Basic (in usd per share)	$ 0.02	$ 0.09	$ 0.45	$ 0.31	$ 0.02	$ 0.09	$ 0.44	$ 0.27	$ 0.86	$ 0.81	$ 0.72
Diluted (in usd per share)	$ 0.02	$ 0.08	$ 0.45	$ 0.31	$ 0.02	$ 0.09	$ 0.44	$ 0.27	$ 0.86	$ 0.81	$ 0.72

Subsequent Events (Details)

Subsequent Events (Details)	Oct. 02, 2017USD ($)debt_instrument	Sep. 30, 2017
Subsequent Event [Line Items]
Promissory Notes term		20 years
Subsequent Event | Roanoke Gas | Unsecured Debt | Unsecured term note payable, at 3.58%, due October 2, 2027
Subsequent Event [Line Items]
Number of unsecured notes | debt_instrument	2
Promissory Notes term	10 years
Debt instrument, face amount | $	$ 8,000,000
Stated percentage rate	3.58%